Chevy 350 missing under load

Jun 18, 2012 · Though I tested all of these first I had no way to test it under load. I bought a Elm32 I think it is called ODBII scan tool and app for my phone. With these two tools I was able to drive and record what the truck was doing when I felt the jerk/miss it was doing. The app actually showed each cylinder and recorded how many misses it had. Checking the plugs. All looked like the two you see. This may not be easy to figure out :-) Oct 16, 2008 · I have a street rod with a chevy 350, today when I took it out it started running rough under load, it sounded like a popcorn machine, so I turned around and parked it, the temp on it was 234 degrees, … read more Cross-firing due to bad sparkplug wires (if so equipped), a bad distributor cap (if so equipped), too lean a mixture causing pre-ignition, vacuum leaks, too much spark-advance causing pre-ignition,... Jun 13, 2004 · Well ive been trying to get this new 401 to run well and just havent had any luck. it idles great and runs smooth until after about 2500 rpms and it gets under load or you stab the throttle then it backfires or pops. it did it with my edelbrock 1406 and edelbrock q-jet. it now does it with the Howell TBI kit i just installed today. Jul 02, 2010 · I have a 97 silverado 350 when under a load it misses and backfires and at cruising speed it jerks - Answered by a verified Chevy Mechanic We use cookies to give you the best possible experience on our website. Dec 25, 2005 · I have a 350 with HEI distributor. When my RPM's get over 2000 the motor starts missing. I have changed the cap, rotor, plugs and wires. I can't check my timing cause all my plugs had to be rotated clockwise by one post for the car to run. Help with 98 Chevy 5.7 misfire not running right 28 Answers. Hello. I have a 98 chevy 1500 5.7. The truck doesnt run right at all. Msifres bad under acceleration. Idle ok when misses when reving and accelerating. I did a full tune up including plugs, wires, cap... Running fp should be about 6-7psi ,under load wide open 3-5 for sure. Get the timing where it should be to eliminate any questions, clogged sock in the tank causes issues also. Martin86 Engine misfiring usually results from simple, easily fixed problems. Engines most commonly begin to run roughly or miss as a result of wear and tear on components, which you can find at your local auto supply store. The problem usually stems originally from water, dirt or wear and their effect on engine performance. I have a Chevy K1500 sierra with a 350 that is not EFI. That’s a long story from when my project began. OK, I bought someone Else’s problem. Replaced the engine and it starts and runs fine, until you drive it under load. I’ve checked the timing and it’s set at +2 degrees. I rebuilt the carb (not the problem) Replaced fuel filter which was not plugged. Vacuum advance seems to be working ... Dec 25, 2005 · I have a 350 with HEI distributor. When my RPM's get over 2000 the motor starts missing. I have changed the cap, rotor, plugs and wires. I can't check my timing cause all my plugs had to be rotated clockwise by one post for the car to run. Jun 25, 2007 · A high-perf fuel pump should fill up a 1-gallon bucket in well under a minute. ... open on a real-world running engine with the car in gear and/or under load.) ... 1966 Chevy Chevelle Classic ... Jun 13, 2004 · Well ive been trying to get this new 401 to run well and just havent had any luck. it idles great and runs smooth until after about 2500 rpms and it gets under load or you stab the throttle then it backfires or pops. it did it with my edelbrock 1406 and edelbrock q-jet. it now does it with the Howell TBI kit i just installed today. These numbers don't seem overly high to me, but I'm still getting pinging under load (not WOT), though not as bad as the day I brought it home. It's been a while since I've worked on a car that didn't electronically control its own timing, and this is my first Chevy, so I'm a bit foggy about what ballpark timing for this engine should be. Misses under load truck empty. Reply 1: Miss under load first thing i would suspect is plugs and wires. Reply 2: Im thinking camshaft. Plugs,wires, ... Engine misfiring usually results from simple, easily fixed problems. Engines most commonly begin to run roughly or miss as a result of wear and tear on components, which you can find at your local auto supply store. The problem usually stems originally from water, dirt or wear and their effect on engine performance. Jun 25, 2007 · A high-perf fuel pump should fill up a 1-gallon bucket in well under a minute. ... open on a real-world running engine with the car in gear and/or under load.) ... 1966 Chevy Chevelle Classic ... 3 Answers. do this first, "and at night" but this time lightly spray water around the motors wires and dist. have someone run up the rpm's while doing it. don't flood the area but make sure its... Help with 98 Chevy 5.7 misfire not running right 28 Answers. Hello. I have a 98 chevy 1500 5.7. The truck doesnt run right at all. Msifres bad under acceleration. Idle ok when misses when reving and accelerating. I did a full tune up including plugs, wires, cap... We look at our new Camaro to see if the engine is dead. We find low oil pressure. We find loose rocker arms on a soild lifter cam. We find low compression on... 3/4 ton, 350 TBI engine with 125,000 miles. The engine misfires or runs rough when it is fully warmed up at constant speed or stopped and really bad when pulling a load up a hill or when power breaking. Under a load on a hill it feels like I am loosing one or two cylinders. I have a Chevy K1500 sierra with a 350 that is not EFI. That’s a long story from when my project began. OK, I bought someone Else’s problem. Replaced the engine and it starts and runs fine, until you drive it under load. I’ve checked the timing and it’s set at +2 degrees. I rebuilt the carb (not the problem) Replaced fuel filter which was not plugged. Vacuum advance seems to be working ... it idles fine and revs in idle fine but when you drive it or brake torque it, it kinda missfires putts and when you let off the gas it dies. done a full tune up. replaced computer and coil and checked the timing and still same issue. i also have a 90 tbi truck that runs fine and the timing is... Can someone please help with what I should check next, I have a 1998 Chevy K1500 5.7 Vortec with a misfire, P0300 code for 3 months. runs a little rough, while driving under normal conditions it sputters, hesitates, and also will backfire, under heavy acceleration no noticeable skip, no sputters, and does not hesitate or backfire. Jul 24, 2012 · There are lots of varying factors effecting engine operation. Temperature, humidity engine load, fuel conditions etc. the fact that it is missing only while driving is proof enough there is a problem that shows up only part of the time under certain conditions. Changing carb to run a bit richer is one easy way to rule out a lean miss. Engine misfiring usually results from simple, easily fixed problems. Engines most commonly begin to run roughly or miss as a result of wear and tear on components, which you can find at your local auto supply store. The problem usually stems originally from water, dirt or wear and their effect on engine performance. Sep 12, 2006 · My car will rev to 5,500 rpm in neutral. But when im under load it wont rev past 4000 rpm, (and iv got the pedal to the floor ) the rpm stays constant. It only does this when the car is warmed up... Iv gone through the fuel system -8psi @ 97gph, and the ignition system -HEI-(new coil, ecu.) Iv played with the timing countless times to no avail. I have a Chevy K1500 sierra with a 350 that is not EFI. That’s a long story from when my project began. OK, I bought someone Else’s problem. Replaced the engine and it starts and runs fine, until you drive it under load. I’ve checked the timing and it’s set at +2 degrees. I rebuilt the carb (not the problem) Replaced fuel filter which was not plugged. Vacuum advance seems to be working ... it idles fine and revs in idle fine but when you drive it or brake torque it, it kinda missfires putts and when you let off the gas it dies. done a full tune up. replaced computer and coil and checked the timing and still same issue. i also have a 90 tbi truck that runs fine and the timing is...

We look at our new Camaro to see if the engine is dead. We find low oil pressure. We find loose rocker arms on a soild lifter cam. We find low compression on... Dec 18, 2005 · My 1994 GMC K1500 5.7 did the samething, I replaced the distributor with a reman. and it still didn't fix the problem, I took my truck to the local gm dealer, they pulled the dist. and tested, the reman was built different from the oem, the top of the shaft where the rotor sits was rounded and the rotor when cold would woble. Cross-firing due to bad sparkplug wires (if so equipped), a bad distributor cap (if so equipped), too lean a mixture causing pre-ignition, vacuum leaks, too much spark-advance causing pre-ignition,... Dec 18, 2005 · My 1994 GMC K1500 5.7 did the samething, I replaced the distributor with a reman. and it still didn't fix the problem, I took my truck to the local gm dealer, they pulled the dist. and tested, the reman was built different from the oem, the top of the shaft where the rotor sits was rounded and the rotor when cold would woble. Jun 13, 2004 · Well ive been trying to get this new 401 to run well and just havent had any luck. it idles great and runs smooth until after about 2500 rpms and it gets under load or you stab the throttle then it backfires or pops. it did it with my edelbrock 1406 and edelbrock q-jet. it now does it with the Howell TBI kit i just installed today. Symptoms----cold drive-ability, bucks @ part throttle, worse under load, backfires, belches black smoke(you should see my tailgate ) Timeline and service related incidents--- Little over a year ago, it quit a couple times---I mean locked down like the key was switched off. I have a 71 Chevy Nova with a 350 motor. It has been running great until a couple of weeks ago. My motor seems to be missing/backfiring once it warms up (about 10 minutes) and I go from an idle to accelerate. It seems to be an ignition problem. I have checked my timing when warm, and when I am at idle, the timing is varying plus minus 4 or 5 ... If you can rev the engine with no load, but the engine stumbles and falls on it’s face when a load is imposed, the fuel pressure is the first thing to check. Tester patricksullivan 1988 Chevy Truck misses under load. KBL9697. MEMBER. 1988 CHEVROLET TRUCK. V8. 4WD. MANUAL. 200,000 MILES. Fuel filter is new, 350 engine, throttle body injection will chug and miss under load when engine warms up but runs fine at idle. These numbers don't seem overly high to me, but I'm still getting pinging under load (not WOT), though not as bad as the day I brought it home. It's been a while since I've worked on a car that didn't electronically control its own timing, and this is my first Chevy, so I'm a bit foggy about what ballpark timing for this engine should be. I have a Chevy K1500 sierra with a 350 that is not EFI. That’s a long story from when my project began. OK, I bought someone Else’s problem. Replaced the engine and it starts and runs fine, until you drive it under load. I’ve checked the timing and it’s set at +2 degrees. I rebuilt the carb (not the problem) Replaced fuel filter which was not plugged. Vacuum advance seems to be working ... Running fp should be about 6-7psi ,under load wide open 3-5 for sure. Get the timing where it should be to eliminate any questions, clogged sock in the tank causes issues also. Martin86 Mar 24, 2010 · i have the exact same issue (chugging under heavy load). Done everything you've done too. Got a little better but not completely. right around 3000 rpm is where it starts. Mines a 5.3 vortec though. I change the fual filter and that didn't fix it but it got better. It was real bad before i started tuing it up and it's much better now but still ... Oct 28, 2015 · Re: Hesitation an backfire under acceleration Nov 03 2015, 11:19pm Thinking it maybe clogged cat or cats, but I checked my fuel pressure today and with key on and engine off it read 50 Psi, then running it drops down to about 47psi,hopefully it's not the pump or bad check valve on the pump,hopefully clogged filter being that I replaced the pump ... Sep 25, 2017 · Internally stock 1978 Chevy 350 with an Edelbrock manifold and carb and dual exhaust in my '53 Chevy. The engine has around 70,000 miles on it. Turbo 350 trans and 3.42 rear end. I have always run 87 or 89 octane gas and no problems except under load occasional ping with 87 in the tank. Mar 24, 2010 · i have the exact same issue (chugging under heavy load). Done everything you've done too. Got a little better but not completely. right around 3000 rpm is where it starts. Mines a 5.3 vortec though. I change the fual filter and that didn't fix it but it got better. It was real bad before i started tuing it up and it's much better now but still ... I have a 1996 Chevy Silverado 5.7, Everything is stock, have never had a problem. Lately it has been lugging, spitting and sputtering pretty bad and only getting worse. The best way to acknowledge the problem is to come to a dead stop and stomp on the gas. It used to chirp the tires a little... Re: 350 sputtering under load « Reply #13 on: March 04, 2015, 09:58:08 AM » Sure hope you caught it in time,I know it sucks ,I just went through the same thing with 0 miles on my truck.I can't tell you how many carbs I've put on new out of the box that didn't need something done to them.I just put a quick fuel carb on a Pontiac that floats ... Oct 28, 2015 · Re: Hesitation an backfire under acceleration Nov 03 2015, 11:19pm Thinking it maybe clogged cat or cats, but I checked my fuel pressure today and with key on and engine off it read 50 Psi, then running it drops down to about 47psi,hopefully it's not the pump or bad check valve on the pump,hopefully clogged filter being that I replaced the pump ... Mar 24, 2010 · i have the exact same issue (chugging under heavy load). Done everything you've done too. Got a little better but not completely. right around 3000 rpm is where it starts. Mines a 5.3 vortec though. I change the fual filter and that didn't fix it but it got better. It was real bad before i started tuing it up and it's much better now but still ... Checking the plugs. All looked like the two you see. This may not be easy to figure out :-)