Truck hesitating when it gets warm?

[Abaddon]

I used to have a 1993 6cyl but I gave it away because it was starting to get old (175k on the poor truck). The guy I gave it to has been having some problems and I wondered if anyone would help. When the truck warms up, it starts to bog down before it gets to the top of the gear. If you are climbing a hill it bucks and kicks and you have to pull off the road and let people buy. I'm starting to wonder if it's a bad cat. Here's what the guy has tried so far.

Stuff that has been tried: Replaced O2 sensor, ingnition coil, TPS, vacuum lines, drained the gas tank, new fuel filter, and rotor button and dist cap replaced

Does anyone have any ideas on what this might be or how to fix it? The guy really wants to use the truck for work. Thanks!

[Mikz86TA]

Is there any idle issues? Is it TB or CPI?

[Abaddon]

Is there any idle issues? Is it TB or CPI?

It idles flawlessly. If you punch it while the truck is out of gear, it bottoms out before it reaches redline. Not sure what CPI is. It's a stock 2.8l v6 1993 S-10. That help?

[SCredneck]

You say you already replaced the cap/rotor. I'll bet new plugs and plug wires will do the trick. A clogged cat wouldn't usually make it "buck and kick". Just refuse to rev and have no power b/c it can't breathe. Also will usually make it run hot. If it's idling fine and only acting up under load, I'll bet a cheeseburger that a new set of plugs and wires will do the trick.

[Abaddon]

Plugs and wires are less than 3 months old. They are still nice and clean. Maybe one of the wires has gone bad?

[SCredneck]

I just had to replace a set of Bosch wires on my 4.3 that was only 2 weeks old. It CAN happen. Especially if not really careful about the routing of the wires where they are close to the exhaust manifold.

[SCredneck]

Did ya get it fixed yet?

[$1S-10]

Hi, Thanks for trying to help me with the truck. I'm the person that got the truck from abaddon. This is what i have done or replaced

Replaced O2 sensor, ingnition coil, TPS, vacuum lines, drained the gas tank, new fuel filter, rotor button, dist cap, plugs, plug wires, reset the timing, and tried another computer.

The truck will set at idle ok. It is when you start to take off it bogs down and starts to stall. Now cold or hot. When I tried the other computer I reset it so if it had any stored codes I would get confussed on which error codes where mine. So now when I run it to get the error codes it doesn't show any. It just flashes code 12 which is diagnostic mode, so it is acting like there is nothing wrong. Could there be something wrong with the tbi or map sensor? I would be very thankful for any input.

[manofthehour114]

One of my buddies had the same problem with his K1500. It would only rev to about 4000 rpm, then it started missing like crazy. He replaced the timing chain and the problem was fixed. The only thing we could figure out is that there was enough slack in the chain to cause the timing to advance itself at high rpm, and thus causing bogging.

Maybe try that????

[SCredneck]

With 175K on it, it's time for new chain. Just put new chain on mine (263K) a few days ago. Big difference. My next guess would be clogged or dirty injectors.

[pappyl]

Check the timing, make sure it hasn't wandered.

Get the engine warm, undo the EST wire (should get a code).
When you have it on base timing, rev it a few times, and watch it. If it's wandering a lot (ie: jumps around back and forth on the timing mark), indicates a sloppy chain.

[$1S-10]

When I first checked the timing it was way off. But then you could kinda drive the truck untill it got warm and then it would start stalling on take off or high speeds(60-70). Since I've adjusted it to the correct timing mark it doesn't matter if it is hot or cold. As soon as you start it up and take off it trys to stall. I'll let it idle for awhile and rev it a couple of times and then recheck the timing. I'm going to get a fuel pressure gauge to check the fuel pressure. If thats ok I'm going to rebuild the tbi unit and if that isn't it then I'll look to the chain. With 175k its not like it wont hurt it to have it done :). Thanks to everyone that is posting.