1996 Buick Park Avenue Backfires thru intake on acceleratio

Tiny
ROD S
  • MEMBER
  • 1996 BUICK PARK AVENUE
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 134,000 MILES
96 Buick Park Ave, 3800 V6. Intake gaskets failed, may have liquid locked. Replaced upper intake, there was coolant in cylinders. Blew out cylinders, checked compression, #2 cylinder 140psi, all the rest 185psi. Installed new plugs, car starts good, idle seems smooth.
Hesitates severly on acceleration, backfire thru intake. Check engine light on. Scan tool data shows random misfire(no specific cylinder). Engine vac 16-17hg, st trim
5.6, llt trim16.4, map9.5, maff.636, timing-16, fuel pressure
42psi, and 52psi with reg unplugged. No perceivable vac
leaks, tried coils, maff, map, iat. Engine appears to be running lean, thought about injector problem, but car ran
good before intake problem. Is it most likely that one bent rod, and 45psi drop on one cylinder can
send this car to the wrecking yard. I am sure someone has been thru this before.
Sunday, May 2nd, 2010 AT 6:33 PM

1 Reply

Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
If you hydro locked the engine, then #2 may have a bad ring, or cracked/warped head or rod bent.

Only way to know is to take head off, and oil pan and look at rods.

But a 45psi difference is too much.
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Monday, May 3rd, 2010 AT 8:43 AM

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