i have a 2002 chev 1500 6.0L,235000km,4x4,4door,and this truck as mystery that should be on unsolved mysterys.Long story short,this truck is lacking major power,this is what i have done,multipule fuel pumps,fuel filters,fuel regulator,cleaned fuel rails,new PCM,new plugs,plug wires,compression is normal,new clutch fan,thermostat,new exhaust manifolds,new battery,even put a superchip programer in ,to see if it would help,I NEED HELP PLEASE,thank you

 

you want power from a aftermarket point of view? cuz i have some great suggestions...might sound stupid but gotta excuse me for not knowing much about the trucks but before i start...what liter is it? diesel? are u on a budget? and what time frame are you expecting to be complete?

 

first question, are there any codes? and by lack of power are you talking that it's a serious lack, or just not enough for you?

 

hey whats up max... got bored today and went on a cruise didnt hit on the car just a easy 30-40mph cruise around my city...felt good as hell....now i have another problem.....fuel pump gets weak after a while so ima get ELD performance to install a external also...still got the chatter i gotta adjust my TV cable cuz its unhooked and i cant use my passing gear!

 

have you checked your throttle position sensor?

 

Hi knudles,

Welcome to the Chevy Forums.

OK, over 160,000 miles, let's see, How are those Catalytic Converters? Rattling any?

Changed the transmission filter every 40K as recommended?

Do you ever get a backfire?

Have you tried hooking it up to a vacuum gauge?

What's your transmission type and differential ratio?

 

I would agree with the Cats... have u checked the distributor cap and plug wires

 

My guess is it's a 1500HD truck being that it has the 6.0 in it. I had a 2002 GMC 1500HD and it SUCKED big time...just as you describe...no power....gutless wonder !! Sucked fuel and hardly got out of it's own way !!. My 2000 1500 X-cab with a 5.3 would out run and out pull it. Sold it REAL quick and bought my first D-max. A buddy also bought a 1500HD Chevy (2004 I think his was)....and nothing changed since my 2002.

Unfortunately I think it's the nature of the beast if that's what your truck is.......

 

With it being a 1500HD, which gears do you have? that could be an issue. Also, if you get a custom tune, not that hypertech, or edge programmer B.S., a true tune, you'd be amazed at how it opens up your truck... Trust me.

 

I think the OP has deserted us, I asked about the diff ratio 4 posts ago...