1988 Chevy K1500 hesitation when accelerating

bunderwood93 · August 11, 2014

I have a 1988 Chevy K1500 5.7L 350ci TBI truck and it has been acting up here lately it all started about a month ago. I would go to accelerate while going down the road and it would hesitate and bog down. When it happens I can feel a pulse in the gas pedal and hear an audible sound in the engine compartment(it sounds as though the throttle body is slamming back into place as though its not recieving enough gas). The truck DOES NOT act up during idle or when running at low speeds, ONLY WHEN ACCELERATING. And the problem does not happen everytime I drive, it happens here and there.

I have checked the spark plugs and they are a brown color on the tip which tells me that there isn't a rich/lean problem with the plugs. I have also changed the fuel filter, which was FILTHY, after I had gotten the new filter installed I dumped the contents of the fuel filter onto a rag and the contents were a silver/greyish substance. I have not heard of a filter having this color debris in it, so I am wondering what the debris is and what is causing my truck to hesitate?

The hesitation only happens when I press the gas pedal down a good ways to accelerate, like going up a hill or after a stop light when I am trying to reach the speed limit without creeping up to speed. After I changed the fuel filter the truck ran fine when I took it out to test that fix, and I thought that is had fixed it because I would stomp on the gas to put it in high hear and see if it would hesitate and it did not. The next day I went out and the problem had returned, so it doesn't happen all the time, but it happens more than not.

I only run Shell 93 gas in the truck and take very good care of it. I have gotten to a point where I can't figure out what is wrong with out. I have also taken the air filter housing off and started the truck to see if the injectors are giving an equal amount of gas and they are. I have tried to put everything wrong and that I have done in this post that I can think of, if y'all have any more questions feel free to ask. I would appreciate any help at all with this problem! Thank y'all!

00Silverado4x4 · August 11, 2014

Sounds like you may need to test your fuel pressure. The residue you found in the filter may be the internals of your fuel pump getting ready to go.

bunderwood93 · August 15, 2014

Sounds like you may need to test your fuel pressure. The residue you found in the filter may be the internals of your fuel pump getting ready to go.

I hope that the pump is not going bad, had it replaced in Dec of 2012, but thats not to say I got a bad one.

bunderwood93 · August 15, 2014

I think I did however solve my problem, I asked a friend of mine what he thought of my situation and he said that it might be the plug wires or a wire. I went outside one night and popped the hood to see if I could see sparks or an arc, and darned if it won't sparking. So, I went and got some new plug wires and changed all 8 of them, and the truck hasn't messed up since I changed them two days ago. I am hoping that this was indeed the problem.

The wire I saw the sparks coming from I inspected when I took it off, and it had two spots where the insulation on the wire had cracked and the wire in the middle was exposed. So, I am chalking this one up to bad wires and if the truck starts to mess up again I will update the post. Hope this helps anyone else with the same problem, because it is a cheap fix!