1991 Buick LeSabre Custom Limited rough idling
#11
Retired Senior Admin
Expert Gearhead
Join Date: May 2006
Location: Sheboygan Wisconsin
Posts: 29,661
Likes: 0
Received 29 Likes
on
25 Posts
Have you checked your fuel pressure. For the most part rough idle is a vacuum leak. have you inspected your EGR tube. You can't test this by spraying carb cleaner on it. You actually have to take it off and hold it up to light. The only sensors that can cause rough idle is the IAC, make sure it'* all clean, if not that cone won't seal up. The MAF sensor can cause problems if it'* dirty.
#12
Have you checked your fuel pressure. For the most part rough idle is a vacuum leak. have you inspected your EGR tube. You can't test this by spraying carb cleaner on it. You actually have to take it off and hold it up to light. The only sensors that can cause rough idle is the IAC, make sure it'* all clean, if not that cone won't seal up. The MAF sensor can cause problems if it'* dirty.
Thanks for the input, I'll post again later after I've had a chance to revisit these possibilities.
#13
Retired Senior Admin
Expert Gearhead
Join Date: May 2006
Location: Sheboygan Wisconsin
Posts: 29,661
Likes: 0
Received 29 Likes
on
25 Posts
Sometimes that'* what you need to do. Plenty of times I've been scratching my head, then finally walk away. I'll be sitting there when it comes to me. You will get it, and then smack yourself, dang, why didn't I think of that right away. When you shut the engine off, listen real close, do you hear any hissing?
#14
Senior Member
True Car Nut
I would OHM out the coils, not just to make sure they are within spec, but also the closer they are to each other, the better. The other thing I would ask about? How clean is the engine? I would run a seafoam treatment, blast the crap out of it, then change the plugs again.
#15
Senior Member
True Car Nut
Join Date: Jan 2011
Location: Michigan
Posts: 3,344
Likes: 0
Received 0 Likes
on
0 Posts
its either a custom or a limited, it cant be both :/
I had this problem once, one day I started my car and it sounded like a derby car had no idea what was going on, took it to a gm dealership they ran it for a little while and suddenly it was fine again. Apparently there was a chunk of engine sludge in a line somewhere causing it to cough. Try running it for a while, do the sea foam deal, and start using gumout when you do oil changes. I started that routine (minus sea foam) and my 96 lesabre custom runs like a champ.
I had this problem once, one day I started my car and it sounded like a derby car had no idea what was going on, took it to a gm dealership they ran it for a little while and suddenly it was fine again. Apparently there was a chunk of engine sludge in a line somewhere causing it to cough. Try running it for a while, do the sea foam deal, and start using gumout when you do oil changes. I started that routine (minus sea foam) and my 96 lesabre custom runs like a champ.
Thread
Thread Starter
Forum
Replies
Last Post