gospel25514

1997 3.1L
Hey Fellas, I finally changed my AC compressor and my whistling noise is gone. The hesitation still remains. Pulled my front 3 spark plugs and they appeared dry and very white. There was no build up but like a white powder coat on all 3 AC Delco plugs. Also noticed with the car in park when I rev the engine you can hear what appears to be a popping noise coming from the exhaust. It is not like a rifle backfire but like a low pop pop pop. Could my Cat be clogged? Car has 74,000! What would cause the white powder build up?
Thanks
Gabe

maxwedge

Plugs sound normal, how high did you rev the engine? There is a pcm cut out at 4k.

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gospel25514

Hey Max...the popping happens when I quickly rev about 3/4 and let off quickly. The popping occurs as the engine is on its way down to idle. I am just stumped about the power loss. I have replaced the plug wires and fuel filter. It is like you are accelerating with low power and then it will just pick up and go like normal. Seems to idle ok with a little miss that at times isn't even noticeable. Is there a way I can check the cat without the vacuum test? I mentioned the vacuum test to an exhaust service in town and they didn't even know what I was talking about. They say it will have to be cut and examined

jeffcoslacker

A serious blockage can be spotted with a vacuum gauge. A cat on it's way out can also be diagnosed with a pyrometer...different parts of the cat operate at specific temps, too much or too little heat indicates problems.

You don't sound like the typical cat scenario though...it usually first shows up as a flattening out and refusal to "get up and run" like when trying to merge onto a highway or pass someone, the engine doesn't want to rev and looses more power the harder you step into the gas...sometimes the motor will run hotter than normal at higher speeds, sometimes not until the problem gets real bad though...

Anyway, if you had a cat restriction problem it wouldn't break through and suddenly get up and run...it would just get worse the harder and longer you tried to accelerate...

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You made three mistakes. First, you took the job. Second, you came light. A four man crew for me? F**king insulting. But the worst mistake you made...

...empty gun rack.

gospel25514

Jeff... I have this problem with the car if the car has been run for a while as to say in town. Perfect example today in town ...I had to run for quite a while in town stopping at lights and traffic. After about 20-30 minutes I went to accelerate at the light and at about 30-40 mph car acted as if no gas was there no spidder or spudder you could push the gas pedal to the floor and no rev just a creep but the car will not quit running and after I let off the gas and gently apply... it would slowly creep up to speed but it only does it this bad after the car is really warmed up. It is so weird. I have had my share of problems with cars a know somewhat about cars but this has me stumped. It is like the fuel pump is not sending fuel but I put a AC delco on it about 6 months ago. Is there a sensor that may be doing this to me once the car gets hot? When the car is cold as mentioned in my beginning post you can tell a lack of power but it will still go but once hot it is as if no gas is there. Pull off on the side of the road and rev the engine without problem in park just the popping noise ever so often. Seriously aggravating!