I've got a 98 Chevy 1500 with a 350 and over the past couple months it's been losing power. I can't figure out what's wrong. Any ideas?
And I'd also want to know would it be rough on it if I put a chip in it? It's got 202,000 miles and I've heard it's bad on trucks with high miles

 

Your going to post more info about this.

 

I put new plugs, wires, fuel filter, cap and rotor on it about 5,000 miles ago. New O2 sensors about two weeks ago. But the past couple months ago it had no acceleration and feels like I'm having to press the pedal down way harder then normal to keep it up to speed. When I pull a trailer it feels like its a V6. I checked all the plugs and the brakes to see if there dragging. It doesn't use any oil. 4 months ago it could beat any other Z71 in a race but now a stock one would leave me in the dust. Half the time if I get on it it won't even down shift

 

Hey an idea check the pcm, if you step on the gas an the pcm is not advancing the timming no power..ya get one from junk yard an try it..let us know....

 

Check engine light came on today. I ran the code and it had 4 codes. Low circuit, insufficient power, running to lean, and O2 sensor which I had already replaced two weeks ago. They gave me a new one free and I put it in so I guess it was just a faulty O2 sensor and I'll see if it fixes it

 

I believe there are a total of 4 o2 sensors, before after the CC on both exhuast pipes

 

All 4 were replaced. Two after the CC's wouldn't do anything for how my engine runs. They just tell me if I have cats or if there blown. Two before were replaced to and the one that was bad was on goes to passenger side manifold and every plug on that side was black

 

This happenend to our 98K3500 5.7 a few yrs back. Turned out the cat converters were plugged and were resticting the exhaust to the point of not having any power but started and idled fine. Our plugs were black also and if you split the exhaust and it runs better thats a clue

 

Today pulling out of my driveway for work it felt like 1st gear was out in my truck. I pull onto my road and get on it and it wouldn't even spin the tires and it's a gravel road. I took the air intake off the throttle body and while it was running and the truck died immediately. Shouldn't it run with that off? My experience with trucks like mine they ran just fine with no air box in it. I'm stumped and can't figure out what's making it do this.

It weighs 4500 pounds and scrap metal is 10 cents a pound right now. $450 is looking pretty good right now

 

Did you try bypassing the cat's,when you pull the intake off the throttle body the air flow signal to the computer goes to zero i never tried this so i dont know if it should stall but i would think it would **** the computer off at a min,did you do a compression check