Surging at idle/rpms up and down then dies

We cant drive it. if we push the gas , trying to feather it so it doesn't die right away it ends up with a big backfire. if I just let it try to idle it dies out after 30 secs to a minute. We were towed home and it hasn't moved since. My husband was watching injectors when I was trying to give it gas and even with it surging the spray remained the same. Could it still be a bad fuel pump? We had the distributor module tested and it was fine, however the pickup hasn't been dealt with yet. I am going to have a new truck by time this is over!

Replacing pickup coil today. Noticed when rpms dropped there was no spark. Coil is new and most everything else is new. Hopefully the pickup coil is the culprit!

Pickup coil did not work. Now what? We are at our wits end!!!

My 1992 Chevrolet CK1500 4.3 TBI has been doing the same as yours for about 6 months and has gotten progressively worse. I would suggest checking the wiring that is going to all these sensors that have been replaced. Good possibility that little mice or ??? could have gotten in there and chewed some of the wires just enough to make things go awry. Contacting Chevrolet Motor Division,( to find out if these trucks had a bulletin put out on them ) , would be a good idea as well. Good luck with your truck

Thank you aunttilly. Hubby checked wires and grounds today. He even readjusted valves, just because. Everything has been replaced. Seems to be worse as it won't stay running now. The only thing left is the computer.

Did you have the coil checked or replaced yet ? That was going to be my next move. Also, I contacted GM to find out if there were any technical bulletins, ( TSB ), on the 1992 CK1500's with the stalling / no start problems .When I worked for Chevrolet many years ago these were common , but they were not covered under warranty , unlike the safety campaigns. We should be hearing back from them by Monday, 8/13/2018. This is getting a bit ridiculous , as I think you would agree. I'll post as soon as I here from them.

Well, Haven't heard back from GM yet again, however, I did find a website that lists the Technical Service Bulletins on all vehicles. The section for 1992 Chevrolet CK1500 trucks is informative as to what & where the problem areas are, but not the actual fix, ( unless you know someone that works at a dealership). At least it's something to go by . Meanwhile, I sure do miss my truck !

Technical Service Bulletins : tsb.govwebscom

We have now replaced every part we can replace! I will check or the bulletins. Thank you! Have you had any luck yet?

Have to pay for bulletins. I have nothing left but the computer. Just don't know. Everytime we replaced a part it tried to run better for a minute then went back to the same problem. : (

Don't give up just yet.....I went back to that site that showed the bulletins, it wouldn't let me back in without a credit card,,,good thing I jotted down the ones that pertained to 1992 Chevy trucks : / still have to find the fix though. Piece of cake......The big important one was - Bulletin #020604052 Date:Oct. 2002 Summary: Engine Stall, No Start, Hard Start Cond. CNHTSA Item #00000167 (not sure what this is).

Still not much luck on this end.....I did repair some wires at the O2 sensor and also at the knock sensor. Truck started up and almost sounded all better..until it warmed up. Then it was right back to the surging idle then stalling thing. I'll keep trying to get this done though . Plz keep posting. Someone is bound to figure this out. These folks seem to know a bit about automotive bs : )

We still aren't having any luck. The only thing left is the actual distributor and the computer. Just don't feel like it's the computer. "Sigh"

Well, we're still at a loss but now leaning towards the map sensor. Has yours been replaced yet ? We did replace one on our truck but turned out to be one of the old ones that was put away for what reasons I do not know. Are all the parts that were replaced on your truck new ? Seems like a silly question but at this point, not really. We'll keep on trying ...........Please post updates on anything new tried. Thanks & good luck : )

relocate ecm ground from thermostat housing to different area

If it is bucking, put a TPS on it

TPS SENSOR BREAK INSIDE THESE THINGS AND CAUSE IRRATIC IDLE. THE IDLE AIR CONTROL IS ALSO NEXT TO IT PULL THAT AND ENSURE IT ISNT COVERED IN CARBON.IF IT IS CLEAN WITH CARB CLEANER

One item that is always overlooked is corrosion built up on the reluctor wheel sensor within the distributor. Remove the distributor and clean off all the crusty mess from the wheel, you will see it has eight spikes. Clean the pickup magnet area as well. I always replace the inexpensive pick up coil while I am in there. The spike of the wheel passes the magnet and the coil is induced thus sending a pulse to the ECM which in turns signals the fuel injector(s). If there is corrosion you get mixed injector signals which can run rich or lean and... no code gets thrown at you. This also might cause stalling once the engine is running warmer and after letting it cool down it will run fine for awhile, that is typical flooding of the engine if there is enough crud built up in the reluctor area.

After replacing EVERYTHING on my truck except the actual distributor and computer we broke down and got a new distributor. Guess what? truck is running like a champ! Only took 28 parts to get there! Thanks for all the input!

The issue is your detonation caused by a faulty distributor.

WOW! Cant tell you all how relieved I was to read every post describing the exact same things i have done to fix the exact same problem. New Distributor will be replaced today hopefully that will solve my issue as well.

WAY COOL ! SO GLAD TO HEAR YOUR TRUCK IS ALL BETTER, THANK YOU MUCH FOR ALL THE INPUT, I TOO AM GOING TO TRY A NEW DISTRIBUTOR RIGHT AFTER I GET A JOB TO PAY FOR IT : )

Aunttilly snatched mine from eBay for $27. Complete assembly with pick-up coil, control module, cap, rotor, and gasket. Took about a week to get it.

Wow my truck has been doing this for 2 years and I put a brand new crate motor in and replaced every single sensor every single pigtail to the sensor every single thing that anyone ever said I replaced the only thing I haven't replaced is the ECM but I did switch it out with another truck that ran fine and it was not the problem what happens with my truck is when you first start it it runs like it has a huge cam in it and then after about 30 seconds it runs smooth as glass and I just can't figure out what the problem go ahead and name a part I've already replaced it I've already rebuilt it or bought a complete new one I love my truck but I'm really tired of this the only thing I've heard is that it could be a leak in the intake manifold gasket somewhere and I guess that's possible because the crate engine did not come with it installed

Try your map sensor vacuum supply

i love this group guy. Thank you sooooo much

I put new heads on my 94 k1500 about 1 year ago but i had left parts in the back while i ordered parts. Took awhile to get all parts in and after installing I noticed exactly what this thread is describing, idle up and down also I had a pop back through the carb on acceleration. I recently redid the intake gasket after changing tps iac egr control fixing wires new plugs wires cap rotor. Popping is gone so im convinced it was a vacuum leak, error on my part, but the erratic idle up and down and dying, then dies at stop signs and have to feather to keep going has me at wits end. I have set and reset valves, checked and rechecked timing. After reading this Im thinking that my distributor may be the culprit and intend on replacing asap. But I'm curious as to how many of you did this and it fixed your issues of idling up and down. Tia

1988 Chevrolet c1500 5.7, same problem idle up and down, pops on acceleration. Everything I replaced on the truck: computer, egr solenoid, egr valve, distributor, ignition module, map sensor, oxygen sensor, throttle position sensor, coil, temperature sensor, cap and rotor, tbi base gasket, fuel pump, fuel filter, fuel pressure regulator, fixed two vacuum leaks. Still not fixed!!!

I have a 94 Lumina van, 3.1 engine. It was surging, bucking etc. While torque braking, it would rev up, then down with the same pedal applied. After, it would come close to dying. I too replaced everything, TPS, MAP, distributor and injectors. I finally discovered my EGR was opening when I revved the engine. It should not do that. I disconnected the EGR vacuum line and the engine runs fine now. I ordered a new EGR solenoid control valve. It should be here soon. I'm pretty sure that is the problem.

1988 GMC k2500 5.7. surges while under load, have replaced the entire fuel system and distributor. Still does it. Any ideas? Runs fine at first start but once hot it does it.

Did you find the problem??

Check the power booster vacuum. Try b unplugging it and see if the idle levels out.

My 93 1500 same issue, was the brake booster!

1993 c1500, same thing. Turned out to the brake booster........after the 4.3l to 5.7l swap. Thank you all so much for following up with your results!!

1996 silverado 4.3 v6 single cab. Mines when hits 45-50 mph rpm jump up and down.replaced selenoids transmission ,oil trans,filters,spark plugs,wires,o2 sensors,tps,idle control sensor,fuel pump,spider injector,distributor complete, clean thorttle body ,fuel filter any help

JUST FINISHED WITH MY 1992 SILVERADO K2500, HAD SAME ISSUES, REPLACED EVERYTHING POSSIBLE, INCLUDING THREE DISTRIBUTORS, COMPUTER TWICE, CHASED ALL WIRES LOOKING FOR POSSIBLE RODENT ISSUES, MOVED GROUNDS, CLEANED FRAME GROUND TO FUEL PUMP, AND CHECKED ALL VOLTAGES, FOUND FAULTY GROUND WIRE TO BODY, NOT GIVING ECM ENOUGH GROUND, TRIED A JUMPER WIRE FROM BATTERY TO HARNESS GROUND UNDER PLASTIC COVER RIGHT SIDE OF FIREWALL EVERYTHING GREAT NOW!!!