Mechanics

CHEVY 97 5.7L BOGGS DOWN

1997 Chevrolet Suburban

Engine Performance problem
1997 Chevy Suburban V8 Two Wheel Drive Automatic 205000 miles

my suburban boggs down severly when driving and when reving in park or neutral. I have done multiple things to correct this problem to include, new plugs, plug wires, distributor cap and rotor, new spider injector, compression test, fuel pressure test, and finally dissabled the cats to see if they were plugged up. I also checked for vacuum leaks with propane and found none. The plugs are sparking fine and the gaps are good, however, I keep getting a number 6 cylinder misfire code and a left bank oxygen sensor code. That oxygen sensor was replace about a month ago. It started out gradual but has progressed to the point where it is near impossible to make it up a hill. Any one have a clue what else to try? Any suggestions would be greatly appriciated.
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Brichart
May 16, 2008.




Exhaust leak on the side of the bad o2 sensor can cause it, also if your MAF sensor is bad it could be causing this problem, clean it with qd contact cleaner.

205,000 miles? Perform a cylinder compression test wet and dry on all cylinders, make sure the readings are within specs.

Blackop555
May 17, 2008.
Thought about that too, the o2 sensor code is on the opposite bank of the misfire. Also had compression test done by reputable shop in town and they were good. Same shop said the MAF sensor is reading good. Wondering now if the computer could not be advancing the timing correctly?
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Tiny
Brichart
May 17, 2008.
Pull the jumper for the advancement, same jumper used for setting the timing.

Might have to take it in and have the cross fire checked on it with the scan tool.

Check EGR valve also, could be plugged atad, PCV valve good? Double check.

Blackop555
May 17, 2008.

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