1996 Chevrolet Cheyenne Engine Starts Idles Fine Sputters Backfires Gear

1996 CHEVROLET CHEYENNE
110,000 MILES
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FENN49
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Engine starts and idles fine......sputters and backfires when in gear and accellerating. I can accellerate gradually but will not after heating up from driving at speed for a distance. Acts like cats but had them replaced......any thoughts?.......plugged muffler?.......other?
Apr 10, 2013 at 8:49 AM
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HMAC300
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scan for codes and check fuel pressure first then check vacuum at idle if 15" or below suspect clogged exasust also check for vacuumleak.
Apr 14, 2013 at 3:16 AM
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FENN49
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Thanks hmac300......have now replaced entire exhaust and rotor in distributer......tech scanned and also checked for vacuum leak and none detected......says he can't figure out what the problem is......any other suggestions? Do you think plugs might help?
Apr 24, 2013 at 12:42 AM
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HMAC300
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was a compression test done? if so what are the readings? what engine is in this? it could be the spider in the intake but send me the other stuff first.
Apr 24, 2013 at 12:45 AM
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FENN49
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350 vortec......they said they did a compression test but I don't have the numbers......the truck will excellerate steadily but you can't jump the gas.....also loses power on hills
Apr 24, 2013 at 12:58 AM
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FENN49
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This truck was also driven for quite some time with at least one bad cat.....????
Apr 24, 2013 at 1:04 AM
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HMAC300
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what's the fuel pressure if it's not 60-66psi then replace the pump and filter. that was the first thing I suggested but no answer on that.
Apr 24, 2013 at 1:05 AM
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FENN49
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Okay.....thanks.....I'll let you know how I make out!
Apr 24, 2013 at 1:09 AM
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