1989 Pontiac Bonneville LE 3800 CC Motor Injector Mis-Firing #5 cylinder- Why is this happening?

1989 PONTIAC BONNEVILLE
44,000 MILES
Avatar
WILDERTRACY
  • MEMBER
  • 2 POSTS
I have a 1989 pontiac bonneville LE 3800 that i can't figure out.
It's on and off mis-firing on cylinder 5 . Is this something that is normal and what is the problem?
thank you for any information you can give me to alleviate this problem.
with regard,
Tracy
Sep 20, 2011 at 1:50 AM
Advertisement
Avatar
MHPAUTOS
  • CAR REPAIR CONTRIBUTOR
  • 31,937 POSTS
Check compression, plug, lead and vacuum leaks at that cylinder, start here.
Sep 20, 2011 at 2:51 AM
Avatar
JB85128
  • MEMBER
  • 6 POSTS
We almost have the same problem. My 97 bonneville has been having issues with a misfire on cylinder #4. What I have learned so far is that a misfire on one cylinder is most likely a fouled spark plug, bad ignition wire, clogged injector or possibly bad compression such as a burned valve.There may be a slight possibility of a bad coil, but if the coil pack fires two different cylinders then it should misfire on both. I figure a person can change the coil packs around to see if the misfire moves with the coil or stays on the same cylinder.
Oct 1, 2011 at 2:25 AM
Avatar
WILDERTRACY
  • MEMBER
  • 2 POSTS
i have looked at most of those options you both speak of.
i think it may be the computer board.
after i put the dash back together (which will take several hours) i plan on just taking it to a shop to get it fixed.
good luck to you and many thank yous for answering!
Oct 2, 2011 at 2:09 AM
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.