350 chevy runs rough at idle. I have changed the iac, new ...
350 chevy runs rough at idle. I have changed the iac, new plugs, wires, dist. I just replaced the plugs about 3 months back and it ran fine after, people have told me things like it is the o2 sensors to the cat is plugged It s/b 9 - 13 PSI (according to GM specs), at idle and under acceleration, preferably 11 - 13PSI. The issue disappears when you give it more gas and the RPM's increase again. Replaced fuel filter Here The motor is a fresh 350 mild street motor, edelbrock carb, msd dist etcall shoved in an s-10. New o2 sensor. Chevy Forums FREE technical assistance for your restoration and repair. In this Video Josh explains the 4 most common causes for rough idling as well as a few other less common culprits. creditchicken. 72 chevy 350 running rough under load! Engine & Drivetrain Chevy 350 bored . Rough Idle No CHECK ENGINE LIGHT~~~~ EASY FIX, In this video i will show you how to repair your low idle problem quick and easy. Also, the drivers side air/fuel mixture screw isn’t responding the same as it did before adjusting the valves. 7L 350 is difficult to start (hot or cold), and runs rough at idle and under acceleration. 1995 k1500 5. Putting this in as a placeholder; I'm not broken down, but starting the truck up after stopping for lunch, it started idling very rough. Plugs are new and look good. Jun 29, 2025 · While it might just feel like your Chevy’s being a little quirky, a rough idle often signals issues with parts like the fuel injectors, spark plugs, or air intake system. Feb 8, 2014 · 350 chevy idles rough and runs rough??? Check your fuel pressure it should be 5-6 lbs. So rich it will burn Found 4 result (s) for your search 1990 chevy truck 350 tbi runs rough at idle up and down and exhaust stinks bad, bad gas milage too Mechanic's Assistant chat Customer: I have a 1990 truck with a 350 TBI engine that runs roughly at idle, fluctuating up and down. I've read most threads on the subject (much appreciation!), and will try some more solutions today. The engine has run very rich since I bought it 6 months ago, and no amount of idle screw adjustment Here is my issue. Read this Wiki article on HEI distributors. I am having a hell of a time trying to get my 350 to run right. Anyway, we have been chasing a rough idle ever since we got it. Replacing Spark Plugs and Ignition Wires: If the spark plugs are old or dirty, swapping them for new ones can instantly improve how the engine runs. You have a rough idle if you feel the roughness when your car idles, but drives smooth. What an Engine Needs to My 1st post and I'm not a mechanic or anything close to it. I captured a couple of logs, etc, and will review when Hey yall, having a problem on my 94 K1500 with a 350 tbi in it. I fitted a pump producing 7-10psi and a brand new Malpassi bypass regulator fitted with 5/16 inlet, 3/8 outlet to the carb and a 3/8 return line to the tank. It was running fine and then now whenever I find myself at a lengthy stoplight, the motor will start to run rough to the point where it will die unless I put it in park and give it chevy 350 idles fine but runs really bad in gear 1 reading Jump to Latest 9. php) With all the new parts installed along the way, the truck has made an improvement, but it idles great on start up, but when you drop it into gear it still runs rough, gutless almost and struggles to keep a steady idle at stop lights once the truck is warmed up. I just put a new 2400 stall torque converter on the truck and recently put a edelbrock 1406 carb on it. (I don't drive her much still working on it). Edelbrock 1407 was sitting for a very long time so I took it apart run the whole thing through the ultra sonic, put it back together with a edelbrock rebuild kit and put it on my 350 sbc it’s cranks and runs decent for about 10 or so seconds then starts running bad a leaking fuel out of the needle plates and accelerator pump. 150k miles on the truck. The idle is the moment when your car engine is most sensitive. A “rough” idle is just like a normal idling engine speed, except it is irregular and not as smooth as we’ve become accustomed to with our modern, smooth engines. Find out how to diagnose and resolve these issues for a smooth-running engine. NO codes or SES. 39,000 miles. The biggest problem is when I go to steer the wheel in near idle 350 vortec engine runs rough when warm The 1988 - 1998 GMT400 Chevy & GMC Pickups Message Board I've got a 2007 Silverado 2500HD 6. The 1947 - Present Chevrolet & GMC Truck Message Board Network (https://67-72chevytrucks. You need to punch a hole in the plug to pull it out, then you have access to the idle set screw. 7L 350, TBI, Auto, 220Kmiles Its been a great truck, for the most part it runs and drives great! but at low idle or low rpm's it missis,sputters,surges and if im just barely giving it any gas it almost wants to stall out. Some of the most common problems include ignition problems, fuel delivery problems, and cooling system issues. cap and rotor. I feel a decent amount of vibration. . 7 Vortec engine and provide some troubleshooting tips to help you get your vehicle back on the road. I have repleaced the plugs, wires, rotor, cap and so on still the same With all the new parts installed along the way, the truck has made an improvement, but it idles great on start up, but when you drop it into gear it still runs rough, gutless almost and struggles to keep a steady idle at stop lights once the truck is warmed up. org they can really help you build your credit! If your chevy gm tbi is running rich this will help you trou My 350 TBI is running very rough. What could it be? Intermittent problem. Bought a can of Daily Driver 71' El Camino Small Block 350 - Torker II, HEI, Holley 600 1850, Headers TH350 This was a daily driver, ran good everyday I developed some oil leaks coming up from the intake bolts so I decided to pull the intake. Here are 10 reasons why your car engine has a rough idle and what to do about it. 060 with flat top pistons, mild 216 duration cam, sportsman II 64cc heads, EB performer rpm air-gap intake and Holley 600 cfm carb. Could be dirty IAC (Idle Airflow Control). When cold, the engine easily fires right up. 31K subscribers Subscribed Chevy Forums FREE technical assistance for your restoration and repair. Could it possibly be the temp sensor for the ECM - giving it a false reading and the computer is feeding it more gas than it So the past couple months I've noticed my truck has a really rough idle in the mornings when it is cold out, to the point where it has even died before. New coolant sensor. You can feel it shake. Its that round canister looking thing on the front of the intake manifold. Heater hose busted and sprayed my distributor which ended up corroding all the terminals in the cap over the next couple weeks and started running rough Replaced cap and rotor, afterwards, idles fine but when under load it backfires thru the intake I have confirmed firing order and timing (with wire unplugged). 2K views 4 replies 4 participants last post by matt123 Mar 29, 2018 Truck is well-kept and serviced. But at idle it is really rough and sounds like it wants to die. It has a 1990 camaro 350 tpi engine in it. In this article, we will discuss the common causes of rough idle and stalling in a 5. I've seen multiple times the ICM (Ignition Control Module) will wig out once the engine warms up after a while (don't use Chinese junk parts). Model specific subject matter experts, classified ads and more. The engine starts willingly and has power but idles rough. Rough idle and Stalling. but it runs great when accelerating Need to build your credit goto www. Tightened loose spark plug 5. I purchased my 1st 1967 chevelle 3 months ago. Hose barb was broken) 3. The truck runs rough at idle, though smoothes out as the rpm's rise. Jul 20, 2025 · Here are some effective solutions for stabilizing a Chevy engine when it starts to idle rough. Runs fine above 800 RPMS, but when it goes to an idle and the RPM's comes down it runs really rough. I don't get a temp light, and the engine seems to run at normal temp, although I don't have a temp gauge at this time. However when at or near idle in gear not so much. Sticky EGR?? Try unplugging the EGR motor connector and see if it clears up. I have replaced the fuel filter, oxygen sensor, air filter, it doesn't matter which tank I run it on, I've used fuel dryer (Heat) changed pvc valve, could be a injector going bad? Could this be related to it running rich ? these days we have very cold weather, around 18-19° F And one thing that keep's me anxious about this it that i cant get it to idle below 900 rpm. 3L V8 developed the same rough idle on start-up so many others have reported. Car ran great until the other day. Most of you know I installed a rebuilt 350 engine with 350 tranny a couple months back. After reading dozens of forums with multiple ideas I went with the cheapest/easiest first. Does it idle rough immediatley after a dead cold start, like in the morning? these trucks really carbon up the intake. What Causes Rough Idle or Stalling in My Chevrolet? Most Chevy rough idle or stalling complaints trace to fuel delivery (clogged injectors, low pressure), ignition (worn plugs/coils), unmetered air (vacuum leaks, dirty throttle body/MAF), or sensor/ECM calibration. I have had it running but been playing with the tranny due to slow shift issues. SBC 350 Discussion in ' The Hokey Ass Message Board ' started by Hop-up, May 16, 2008. 030" over Stock 1979 350 with a rough idle The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board I have a 350 in my 1982 chevy pickup and it runs rough at idle but runs fine when I am driving. This article covers the common causes, how to spot early signs, and what to do about it. After about a half hour, the engine starts to idle roughly and sometimes stalls. IF YOU ENJOY MY CONTENT BUY M A rough idle in a 1994 Chevy 1500 350 fixed using basic tools! This is only one of the many issues that could cause a rough idle but should be one of the thi My 2013 Silverado with the 5. Plugs look a little bit black but I haven't been noticed any smoke. Last thing to check is your coil. Then it's like it doesn't matter how far out i screw the idle adjustment screw !!! I'm also only getting 15" Hg vacuum at idle 350 chevy - bored . The most common cause of a rough idle is misfiring. com/vboard/index. My 350 TBI in my truck is becoming undriveable with a really bad bog and hesitation/stumble when I try and take off at any rpm or speed. One time Rough idle while in gear???? Almost stalls The 1967 - 1972 Chevrolet & GMC Pickups Message Board Every wonder why your car is idling rough or the RPM is too high when idling? Here are some of the most common reasons why Rough idle, stalling and subpar performance might result from the idle surge and stumble issues. The motor runs pretty good at idle and cruises good as well, but as soon as you stomp on it, it sputters, backfires and misses Why You Shouldn't Adjust the Idle of your Chevy TBI Ben of all Trades 2. The exhaust smells "gassy" like it is running rich. Hooked up Torque pro, and everything seems ok. Right now the problem I have is that after the 350 warms up, maybe after five miles, it starts to run rough and smell like Hey everyone, We bought an '89 Chevy K1500 with a 350 in it and 224k miles, with the nasty Getrag trans I knew nothing about until after purchasing the truck. 0 Vortec with a PO300 random misfire/rough idle issue. Engine runs totally fine in park and has the power it should while driving. No codes to indicate a misfire or pressure issue I have a rebuilt 350 with an older Holley 650 carb. My 1990 Chevy Silverado 5. I have messed with the idle screws a bunch, but nothing seems to help a lot Here is my specs: SBC 355 rebuilt Cam - Crane This is a follow-up video to my question about the GM 5. 2012 Malibu Rough Idle 156000 Mileage Runs/Drives Clean Title $1700!! Cash $2700!! Finance short term $850 down $800 monthly and process fees Credit card payment available Random idle, stalling on over- run, heavy fuel consumption etc. A 350 TBI idles up and down at random is one of the most common. If it is a GM HEI have the module checked or if it has age on it replace it. Leaking intake gasket (Leaking oil from the valley) 2. While I was as it I changed to another distributor of the same Starts and runs/idles rough until you accellerate some the it smooths out and runs like it should. It still starts right up and runs fine at high rpm. 350 sbc, pro billet distributor, msd 6 al, sometimes it runs great and sometimes it sputtuers and chugs and runs rough under acceleration. Feb 17, 2020 · There's an idle adjustment screw on the front driver side of the throttle body housing behind a steel plug. My 350 w holley 4 bbl sometimes runs fine for 6 or 7 miles then will start ideling rough and run rough. 7 TBI stalling out when put into drive or reverse gear as well as stalling at idle and or sever hesit My chevy 1987 chevy Scottsdale with a 350 tbi sometime runs smooth then sometimes runs like its running with half the power or less like it has bad gas or something. I have a 91 Silverado K1500 4x4, 5. In this article, we'll look at some of the most common causes of a rough idle in the Silverado and how to fix the problem. I installed a rebuilt sbc355 into my car and it runs well when I drive it, the only issue I have is that it will not idle well below 1200rpm and is VERY rough below 1000. The exhaust has a terrible smell, and the gas mileage is poor as well. Power seemed to be ok while driving to my next errand. I know there is a ton of stuff on rough idle issues but I have tried everything I can find. I have repaired a few things: 1. Well, it didn't seem to idle rough until a few weeks after we bought Rough idle/low vacuum on chevy 350? I've been working on an El Camino with a 70's Chevy 350 of unknown condition. EGR solenoid replaced (Hose was connected to vent. One day it seems to be idled up to high and then it seems to be idling to low when I think I have it right. The truck has a slight shake at idle and feels like a misfire. Can this problem be from timing, Carb adjustments or what I appreciate the help. 7 tbi. May 31, 2016 · Hello everyone. It runs, sounds, and idles great for about a half hour under normal driving conditions. Leaking vacuum hoses replaced 4. The engine runs great with lots of torque and high end performance but idles very rough unless I hook vac advance to manifold vac and then it smooths out and idles fine. He walks through step by step how to figur 14 possible reasons for 350 chevy runs good until warmed up Chevy engines, like any other engine, can develop a range of issues that might cause them to run poorly or fail to start altogether. So far I have tried different distributor and wires, tightened down and adjusted the (new) carb. It starts right away after 2 pumps and when at idle runs rich,. Pretty much the easy stuff for a guy with my I have a mild crate 350 in my 1969 Camaro with an Edelbrock performer 600 carb, hei distributor, and th350 trans. Also what brand of distributor are you using. No trouble codes and the rough idle only lasted a few seconds. It's pretty much always there, I can get it to behave a bit once I'm moving but that's really only between 20 and 40 mph and that's by hitting the sweet spots Chevy Forums FREE technical assistance for your restoration and repair. I Learn about the causes of rough engine idle and misfires. Sometimes it runs ok it hasn't always done this just started not long ago. If you own a Chevy Silverado and it's idling rough, you may be feeling frustrated. 5uock, roeqnu, y8gkla, drog, lvj2y, f4qr, zuzat, wusfi, bwpkl, f4qvo,