1997 Blazer - Difficult to accelerate

[tmf153]

Hello - I drive a 97 Chevy Blazer, 110,000 miles, 4WD and I'm hoping someone has some insight into what may be causing my car trouble woes:

Midway through a drive up a mountain pass, it suddenly became difficult to hold speed at 60 mph; pressed down hard on gas pedal in order to maintain speed. While driving down the pass, the car progressively slowed down while heading down the steep grade; again, had to press on the gas pedal to maintain speed. No odd smells or sounds during or after drive, no trouble accelerating from a stop, 4WD was not being used, and no warning lights on dash. Had the computer scanned when I got an oil change after the trip and there are no error codes.

I filled up the fuel tank about 20 minutes before symptoms appeared and noticed that the car burned through a lot more fuel than it normally would. I had the following work done in the past 6 months before the trip: full tune-up, ignition coil replaced, ignition switch replaced, oxygen sensor replaced, idle control solonoid replaced, CPI unit replaced, fuel induction service, throttle body service, and MAF sensor cleaning. Fuel pressure was checked out as okay (but a little low).

Car continues to start up, idle and drive okay until I try to get past 55 mph and/or uphill, when I have to press down hard on the gas pedal in order to accelerate. I appreciate any thoughts or comments on what may be causing this issue. (On another note, I just noticed that the windshield wipers work when the engine is off and the head lamp dash light turns on when the head lamps are off. Just thought I'd throw that in since I've mentioned everything else under the sun.

[MT-2500]

Originally Posted by tmf153

Hello - I drive a 97 Chevy Blazer, 110,000 miles, 4WD and I'm hoping someone has some insight into what may be causing my car trouble woes:

Midway through a drive up a mountain pass, it suddenly became difficult to hold speed at 60 mph; pressed down hard on gas pedal in order to maintain speed. While driving down the pass, the car progressively slowed down while heading down the steep grade; again, had to press on the gas pedal to maintain speed. No odd smells or sounds during or after drive, no trouble accelerating from a stop, 4WD was not being used, and no warning lights on dash. Had the computer scanned when I got an oil change after the trip and there are no error codes.

I filled up the fuel tank about 20 minutes before symptoms appeared and noticed that the car burned through a lot more fuel than it normally would. I had the following work done in the past 6 months before the trip: full tune-up, ignition coil replaced, ignition switch replaced, oxygen sensor replaced, idle control solonoid replaced, CPI unit replaced, fuel induction service, throttle body service, and MAF sensor cleaning. Fuel pressure was checked out as okay (but a little low).

Car continues to start up, idle and drive okay until I try to get past 55 mph and/or uphill, when I have to press down hard on the gas pedal in order to accelerate. I appreciate any thoughts or comments on what may be causing this issue. (On another note, I just noticed that the windshield wipers work when the engine is off and the head lamp dash light turns on when the head lamps are off. Just thought I'd throw that in since I've mentioned everything else under the sun.

Fuel pressure a little low is not good.
Fuel pressure has to be up to specs for it to run right.

I wouldn start with a good fuel pressure check/test.The only true test on a fuel pump is to check the direct fuel pressure from fuel pump.
A quick test is to block off the return line and see if fuel pressure comes up to over 100 lbs.
But do not run the pump at full pressure very long.
Also when testing fuel pump and pressure you need to tape a gauge to outside windshield or outside mirror and drive it on the road for 20 -30 minutes
until the pump gets has run a while to check for a pump fading out after hot.

Hard to start cold or hot and fuel pressure testing guide lines.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 100 lbs or more.
And if it has a fast leak down after shut off you have a leak in system.
Post back fuel pressure readings.

[MT-2500]

Strange wiper problems is usualy in wiper module.

[4x4 blazerguy]

If it used a bunch of gas you could have a injector or spider leaking fuel. A leak down test is in order I would think. Also fuel pressure regulator issue. So as said proper testing is the answer. Is there a CEL?

[rprough]

Clogged fuel filter, maybe even a fuel leak in a line. Possibly a clog in the exhaust.