1988 GMC S15 Spark knock or like noise

ASCHACK89

MEMBER
1988 GMC S15
4.3L
V6
2WD
AUTOMATIC
25,000 MILES

I have what sounds like spark knock. The engine lags on acceleration and makes an air popping noise like its missing. I have replaced spark plugs, spark plug wires, distributor cap, rotor, ignition coil, ignition control module. I have even replaced fuel filter and went up it top grade of fuel. Still nothing. I have thought maybe fuel pump but that's a big step to take. Looking for son advice. Thank you for your time.

3 Replies

JACOBANDNICKOLAS

MECHANIC
108,128 POSTS

Can you feel a misfire? Have you checked for trouble codes? As far as the fuel pump, I would check pressure before I took the tank out.

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Friday, September 19th, 2014 AT 5:07 PM

ASCHACK89

MEMBER
2 POSTS

Yea it misfires and no I haven't I don't have a code reader and AutoZone doesn't have the hook up for my truck. I'll have to take it into the shop for a pressure test.