5.7L power loss

Tahoe933 · March 8, 2004

My 95 Tahoe has been running poorly in certain conditions for @ a month.

It starts and runs fine at idle, revs without problem in park / neutral.

Problem is at light throttle and low RPM. It goes through low ok, but not like it used to, and as soon as it shifts to second, it is like there is nothing there. Have to apply alot of throttle to get it to accelerate further. It will not rev past @ 3500 in second, even under heavy throttle. Climbing any hill you can feel the definite lack of power, tranny is downshifting much earlier, much more throttle needed.

It runs fine as long as you are heavy on the throttle during acceleration, and seems to run fine on the level once you are at highway speed. Gas mileage does not appear to be affected.

So far I have:

checked for vacuum leaks

Cleaned TB and air filter- injectors appear to be fine, spraying a nice mist.

scanned w/Autoxray - no codes being generated

TPS appears to be functioning properly - voltage goes up and down smoothly.

Seems like it must be something that only occurs under load.

I plan to test the MAP sensor, and pull the dist cap to look things over.

Disconnect ECM and reset it.

Any other suggestions????

Plugged cat? Sensor problem? EGR?

Colorado Kid · March 8, 2004

Fuel Filter, Fuel Pump?

Rookie · March 9, 2004

Im leaning towards pluged cat. This should have shown up if you used a vacume gauge. it will tend to move slower with a pluged cat. Just my thought

SilveradoWV · March 9, 2004

Dist Cap and Rotor have played many tricks on trucks I have had, might want to check there and go with a high quality cap and rotor like ACCEL or Conrad!