I'm gonna go crazy, does anyone have any ideas?

[blueburbboober]

I'm gonna drive my burb off a cliff...

I've never been so stumped in my life. The dealer wont look at my burb, and the autostores gave up.
(95 GMC suburban, 350 engine, 4x4, 1/2 ton)
I'm having a low horsepower problem, and its only when its under a load, like when i accelerate on the freeway, onto the freeway, and climb grades.

Ive replaced:

plugs
cap
rotor
plugwires
exhaust with 70 series flowmaster and walker CATALYTIC convertor with dual stainless tips
inline fuel filter
O2 sensor
throttle position sensor
fuel PUMP and sock
air filter
had the electronic part of the distributor tested.
i compared the spray of my injectors to that of a working truck, looked the same....

I'll mail the first person on this thread to give me the right answer a 20 dollar bill. I'm dead serious. If noone can figure it out, its gonna be up for sale, cause im sick of it.

thanks for any help i get

-Rob

ps. i have no check engine light on, or anything of the sort. hence why the dealer wont look at it.

[jamesrr]

Rob
I feel your pain, My "burb" has also stumped me.(See 88 bucking)
Your problem seems to be in need of basic rethinking. I'm not one to just throw parts in and see what happens next.
Look, one thing burbs have a reputation for is power
and if yours has low hp begin at the basics
air in fuel in exaust out timing/compression
when you went to aftermarket exaust did you change the cat?? a exaust restriction could be the problem.
If it was me I would disconnect and give it a test run.
How many miles?? I'm wondering about compression.
compression gauges are cheap or can be "borrowed from auto parts stores"
Did you actually test the fuel pressure?
This is also another gauge that can be borrowed
not purchased.
Good luck. let us know

[GMMerlin]

First thing is to check the timing..base and advance
Maybe advancing the timing a few degrees may solve your problem.
Check fuel pressure..should be about 9-14 psi...I like to see at least 12.
Checking compression and exhaust back pressure would be next.


If I get it right...send the 20 to a good charity

[99ssconv]

what about restricted or low vacuum to the map sensor, maybe the throttle body passages are clogged, just a thought.

[stubbornmike]

Originally Posted by blueburbboober

I'm gonna drive my burb off a cliff...

I've never been so stumped in my life. The dealer wont look at my burb, and the autostores gave up.
(95 GMC suburban, 350 engine, 4x4, 1/2 ton)
I'm having a low horsepower problem, and its only when its under a load, like when i accelerate on the freeway, onto the freeway, and climb grades.

Ive replaced:

plugs
cap
rotor
plugwires
exhaust with 70 series flowmaster and walker CATALYTIC convertor with dual stainless tips
inline fuel filter
O2 sensor
throttle position sensor
fuel PUMP and sock
air filter
had the electronic part of the distributor tested.
i compared the spray of my injectors to that of a working truck, looked the same....

I'll mail the first person on this thread to give me the right answer a 20 dollar bill. I'm dead serious. If noone can figure it out, its gonna be up for sale, cause im sick of it.

thanks for any help i get

-Rob

ps. i have no check engine light on, or anything of the sort. hence why the dealer wont look at it.

------------------------------------------------------

The problem to your engine.
You HAVE a lower intake manifold leak.. COULD BE air or water maybe both.. it robbs you of power during take off... the lower intake manifold its made of thin rubber it cracks over time allowing air or raditor fluid in over time

----mike

[dirty dan]

I'm fighting a similar problem on '89 burb. Try advancing your timing by maybe 8-10 degrees(must disconnect EST wire when setting timing and re-connect when done). Should provide more power on highway, but will probably cause a poor idle. Disconnecting O2 sensor puts ECM into open loop and smoothed up the idle on mine. Let me know what happens. I have not been able to isolate the problem. I've gone as far as placing my ECM & PROM into a similar burb and it ran like a dream.

[dirty dan]

I'm fighting a similar problem on '89 burb. Try advancing your timing by maybe 8-10 degrees(must disconnect EST wire when setting timing and re-connect when done). Should provide more power on highway, but will probably cause a poor idle. Disconnecting O2 sensor puts ECM into open loop and smoothed up the idle on mine. Let me know what happens. I have not been able to isolate the problem. I've gone as far as placing my ECM & PROM into a similar burb and it ran like a dream.