HELP ME! Low hp problem.

Hey everyone, im getting annoyed...

I have a 95 GMC suburban. It's quite nice really, i just got it 4 months ago for a great deal, only 8 grand. it has 155k miles on it, and is in pretty good shape. it ran great when i first got it, and in the past 8k miles i put on it, its been loosing horse power. i notice this because i have to drive a VERY steep grade to work each day. i thought it was the plugs, cap rotor, etc. replaced them and no help. i thought it was the exhaust, replaced them and the exhaust guy said my cat was bad, but it still didnt help. new O2 sensor, no help. new in-line fuel filter, and no help. i dunno what else to replace! i bumped the fuel economy up from 14.4 mpg to almost 16 with all these replacements, but it still has the horsepower drop.


so recap, all new:

plugs
cap
rotor
plugwires
exhaust with 70 series flowmaster and walker cat with dual stainless tips
inline fuel filter
O2 sensor

so, if anyone has any suggestions at all, please let me know. i need to fix whatever is wrong before i cant make it over the stupid hill to work. (dang, i cant go to work ;-)

-Rob-

hi i got a 99 gmc surburban its got 103k miles on it and the car started to like not idle right it would shack every so often like vibration

so i changed all the plugs wires distributer cap rotor

and my surburban is a 2500 slt 4x4 its got a huge 7.4 liter engine its a 454 and after all that its still not idleing right


power is there though



and iam woundering what type of surburban do u have cauz u have such a good mialage

mines mialage is like 10-11 mpg

thanks alot

my burb is a 1500 model (half ton) it has 4-wheel drive, auto tranny, and a 350 engine (5.7L).

any takers for some suggestions? im at my ends wit with the stupid thing. it keeps getting worse. i started at 75 mph today and was down to 50 mph by the time i hit the top off the hill, and it had to drop to SECOND gear to make it up.

PLEASE help.

thanks,
-rob

Before I got my 2002 suburban, I had a 98 that had the same problem. It was only after about 90k miles though. After I had sold it because it was getting too bad,I went and bought a new 2002 (what i have now). but after i sold it, the dealer calls me up after a week, and says he knew what the prob was. So I paid the fine, yet didnt even think of asking him about the prob. If I knew, I would want my 98 back. But now my 2002 is just getting better and better. Sorry that it didnt have the solution, but i just wanted to share that story, so you know you are not the only one with that prob.

grrrr, noone knows????????? this is super frustrating......... i tried replacind the throttle position sensor on a hunch, and no improvement. i cant find a single thing left to check. if anyone has suggestions please help me. i REALLY dont wanna take this in to a shop, i know ill get raped......

rob,
"a very pissed off person right now, because i HATE computers that controll my truck. they suck at doing it becuase i would never have this problem if it was carbeurated...."

P.S. GRRRRR *exploitive*

this may be a dumb thought but here goes - is the hill you are refering too a dirt road? and if so have you check to make sure your air filter isn't caked with dirt? You didn't mention changing it. Your sub could be sufficating when you are asking it to perform. -- just a thought.

brand new air filter as well, but thanks for the suggestion. i was thinkin about it more today, could it be my timing that would cause this problem? anyone have any ideas on that? what should the timing be set to if i check it? lemme know your thoughts, thanks guys

-Rob

What about the fuel pump? Slight drop in pressure could not be getting enough fuel? Stab atthe dark

Dr Xtreme

ive been talkin to the dealer quite a bit lately, cause im getting pissed off that nothing is fixing the problem. they said something about a scpi inspection bulletin that will allow me to get some free testing done on the injector system. i have a feeling the problem is either my: injectors, fuel pump, fuel pressure regulator, or the computer system itself. i have no check engine lights on at all, nor have i ever had them on. so if any of you guys know how to TEST any of what might be wrong, im waaaaay open to suggestions. whatever needs to be replaced aint gonna be cheap, thats for sure. the dealer quoted me 135 bucks for a diagnosis if the free test doesnt turn anything up, so i think ill pay up if it comes to that. im fed up with it. ive been half tempted to drive it off a cliff and call it an "accident"

:banghead: :banghead: :banghead: :banghead:

a very annoyed 'rob'

I have a 97 that is doing the same thing. Was talking to my friend the other day telling him and he had a friend that had the same problem. he said his friend found that the timing belt/ chain had stretched and after replacing it it ran fine. I haven't ran it by my mechanic yet but let me know if you find the same thing. By the way, does your service light come on going up the hill?

This thread is almost 6 years old. Best bet is to start a new thread.

//2000CAYukon