1996 Buick Park Avenue Backfires thru intake on acceleratio

1996 BUICK PARK AVENUE
134,000 MILES • 6 CYL • 2WD • AUTOMATIC
Avatar
ROD S
  • MEMBER
  • 1 POST
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.
May 2, 2010 at 6:33 PM
Advertisement
Avatar
MMPRINCE4000
  • ASE Certified Mechanic
  • 8,548 POSTS
  • ASE Certified Mechanic
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.
May 3, 2010 at 8:43 AM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.