why is my 1990 f-150 backfireing threw the plentum
Asked by mherring197636 Feb 09, 2015 at 10:08 AM about the 1990 Ford F-150 XLT Lariat Extended Cab LB
Question type: Maintenance & Repair
my truck is backfireing threw the plentum I have checked the fuel pressure and it idles at 38 psi and drops to 32 psi on rev is that proper pressure if so what ealse could be causeing the problem
6 Answers
mherring197636 answered 9 years ago
351 and over 100,000 I have changed timeing gear and chain in past
possibly a valve. run a compression test if the backfire is consistent and steady
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