Hi I've got a problem with a 1989 Chevy Cheyenne 1500 with a 4.3 Liter V6 that has been running fine and now it will start with no problems runs but will not idle if you feather the gas it will drive ok but still wants to sputter and die. I've had a similar problem one time with a early 90's caddy deville that ended up being bad injectors. Just wondering if I'm on the right track with thinking it could be the same thing? Also the fuel filter was replaced to eliminate that so I'm just looking for some help to figure out what the root of this problem is? I've also wondered if it could be the fuel pump in the tank, however I have yet to check that as it involves dropping the tank or removing the truck bed. Thanks so much for your time in advance with this! Thanks, Matt
Year : 1989Make : ChevroletModel : cheyenne 1500 seriesEngine : 4.3 Liter V6
Replaced the fuel filter, took off air cleaner and tried cleaning the TBI carb that is it so far without taking off the bed to check the fuel filter?? Thanks for your time!
Does the engine make full power if you floor it?
yes it does but sometimes it does sputter a little bit but then it comes right back usually and makes full power it just doesn't want to idle it will die. Same with if you try and drive it you have to feather the throttle to keep it going otherwise it runs pretty good. Hope this helps thanks, Matt
Ok, two things to replace that are pretty easy and should make it run way better and of course idle. 1. Replace the O2 sensor in the exhaust pipe. 2. Replace the Idle Air Control Valve in the throttle body. After the repairs are done then unhook the battery for a few minutes to reset everything.
ASE Master Automobile Technician with over 20 years exp. in this field.
Ok I will give that a try I will let you know how it comes out after I get finished thanks for the help. I'll email you once I've tried it;
No problem. Ill be here if you need anymore help. Thanks.
ok so got those two things replaced it did do the trick with the idle but now it seems to have problems when under load or accelerating it chugs really bad now and almost misfires. I installed both parts per instructions and unhooked the battery for about 2-3 minutes, then reconnected the battery cleaned out the throttle body before starting, went to start it but it took a few times to finally come alive. then once running it seems sluggish so I let it warm up to temp. after that it idles now which I'm very happy for. However now it has a sluggish stumble right as you try to put a load on it or accelerate to where it almost dies then comes back. Not sure as to why this would be happening. If you can shed any light on this it would help out tremendously.
Ok, it sounds like the timing may be a little behind. Try advancing the timing by turning the distributor slightly counter clockwise to advance it a bit.
Is it any better?
Well I tried that and seems to idle smoother just a little but the under load sluggishness is still there not sure why? but when I went to adjust the distributor counter clockwise the truck almost stumbled out which doesn't make alot of sense the cap, rotor, plugs, wires, and spark plugs were all replaced about a year and half ago unless they could be bad again? but overall under load it still doesn't want to run smooth idle is ok could be little better but that could also be something to do with the spark possibly? I don't know I'm usually pretty good with the older motors but these newer ones are much different. Anyways if you can suggest anything else that would be great, you've helped so much already. Thanks, Matt
Ok, first you need to check for vacuum leaks on the intake manifold. If theres none then the tune up items mainly the wires may have failed again.
Ok thanks again I apperciate it! I'll see if I can't replace them after checking for leaks in the manifold area. I'll let you know how it all goes tomorrow I'm gonna go out and look everything over and will check back with you tomorrow if you don't mind.
Thanks again, Matt
No problem, ill be here.
Ok sorry wanted to give you a update its been a few days and I was off work for one of them. But here is where things are at with the truck. It will start but again now will not idle not sure as to why. The only things that have been done since we last talked is I did a complete tune up plugs, wires, cap and rotor did not replace the fuel filter as it was done about 2 months ago. After adjusting the timing advance several times with not too much luck. I ended up doing the full tune up, which did help with the smoother running a little under load but it still seems to have a small hesitation just before giving gas or load I cannot figure this out. If you can help me out with this I'd be willing to throw in another $20 or more. Thanks, Matt
Sorry for the delay in getting back to you.
Does the engine make full power if you punch it?
no it wants to die right away and then hesitation and stumble which is not making any sense right now after it was doing pretty good then now its not. thanks
Ok, has the fuel pump ever been changed?
sorry about getting back to you in a timely manner had alot goin on here. I work at a guest ranch and this truck is one of the ranch vehicles; But no to my knowledge the fuel pump has never been replaced. Could that be a problem to what is going on? I looked for vacume leaks but its really difficult cause I know what they sound like and sometimes with the air cleaner off it sounds like a vacume leak but I've looked just about everywhere I can and do not see or hear the leak, enough to be able to find it. Thanks, Matt
No prob. I totally understand. The pump could be weak and thats why your getting "spotty" operation of the Engine in regards XXXXX XXXXX having power. If the Pump has never been changed it would be a good idea to start there.
Ok we'll try replacing the fuel pump hope that works otherwise I'm not sure what else it could be. Thanks, Matt
Your very welcome. Let me know how it works out.