Hello,
I'm new here but have read on this forum for awhile and just decided to join before junking my car that I love.
History:
1989 Bonneville LE
Got it when it had 179,000 on it and it now has 221,000 on it. From what I can gather a road warrior salesman had it before me and bought it new and it seems to have been maintained very well considering it'* condition..... very clean inside and out, engine burns no oil and all the electronics still work, seats, cruise and all. The only things I've done to the car are replace the alternator, battery, serp belt, the radio and speakers(before problem started).
First problem was a no start one morning and I new that was coming because the alternator had been singing for a month, but no warning lights. Replaced the alternator and battery and all was well.
Shortly after car started to just miss and then cut off at redlight stops and sometimes around curves at intersections, all at low RPM and would crank right back up soon as I put it in park. I didn't pay this allot of attention and figured it was just a clogged fuel filter or bad gas as this didn't happen much.
Then I experienced a change in shifting points for 3 days where the trans would have to wind up to a much higher RPM to shift and then that disappeared. Then one morning while on the freeway the car started to buck like a horse. I had already read on this site about this issue, so I pulled off and unplugged the torque converter selenoind swithch from the front of the trans and made it back home fine. At this point I was convinced the trans was bad, so I took it to the Pontiac dealer. After almost $300 worth of diags they found nothing, so I gave them the OK to drop the trans pan. Pan had allot of metal in it, so at that point I was just about through with a cost of a trans replacement and told them to just service the trans and buttom it back up. Ever since then the trans shifts like it always did, just great. Car runs on the freeway great, but still has the stalls periodically at low RPM'* and mostly when the fuel level is below 1/2 a tank. I've put new plugs in, new fuel filter, run allot of injector cleaner through it too. In all my reading on this site and my car'* symptoms vacuum leaks seem to be predominate with this, checked hose and they look good. My car does have to be filled back up with coolant once a month and the only leakage I can find is on the driveway and only sometimes and in very small amounts. I do wonder where this coolant is going as it'* not on the dipstick!
Check engine light does come on sometimes when the stall occurs, but I don't know how to check that myself, so maybe I need to take it back to the dealer to get the error codes to post here.
I'm just about at my end with this old Bonneville, but it is in such great shape that I want to try and find the fix without spending lots of money. I can't envision such a wonderful car going to the crusher when my gut feeling tells me there is an easy fix here.

Thanks for any help,
Scott

Let'* start by checking for codes.
Click on this link for a short article on getting the codes.
http://www.bonnevilleclub.com/forum/...e=article&k=57

Code 42 is all that is showing with the exception of the code 12.

I found this article that explains the code.
http://www.troublecodes.net/articles...ndrstd42.shtml

I'd start by removing the coils & ignition control module(ICM). Check the grounds going to the ICM mounting plate. Make sure all the electrical connections are clean & tight as you reassemble the ICM & Coils.

Did this, all was fairly clean and tight. Drove the car over the last few days with the same problem, seems to be more predominate when the car is run at operating temp for 10 miles or so and the stalling occurs at stops or low rpm while turning into an intersection. Always starts right back up though.
During the last few days while driving at about 45mph the check engine light blinked one time which I had never seen before while at a steady speed.
Just checked for codes again and the 42 is still there because I haven't cleared the computer, but now have a code 13.

Hey whatever the outcome on this, I really appreciate your help.

Scott

My car was doing the same thing, i checked all the same things then some. it turned out to be a bad computer. http://www.bonnevilleclub.com/forum/...ic.php?t=77913 heres the link to my post. also read the others i had posted, see if your car is doing the same. it will get worse as time goes on if its the same problem. if you know someone with a 3800 of the same era, hook up their computer and take it for a ride. i got mine for 50 bucks from the scrap yard. easy to change. fixed the problem immediately.

As far as the coolant goes, have you ever seen steam wisping from the bay? Sometimes the coolant just evaporates or it is leaking right onto a hot surface and is burning away before it has a chance to reach the ground. Check your coolant recovery tank for cracks (be sure to take it out and fill it with water to really get a good idea), and then just do a good through inspection of everything. Otherwise...at your mileage, its very possible that your LIM gaskets have never been replaced, coolant could be slowly seeping into your intake and being burned off in the combustion process. Does your exhaust ever smell sweet?

i just posted the same problem i had with the same symptoms and code 42 as well.. it turned out to be some loose connections at the wire clip for the ignition control module.. so i got one from my yard and put it on and it runs sweet again and no more code 42..
here is a pic of the wire you should change... they go bad grom the heat and get all gooey and sticky in the clips over time.. and loose contact,

here is a pic of what i got from the yard and cleande it with electric connection cleaner and re covered it in blue..

here is the link
to the pic of the wire you need

http://s177.photobucket.com/albums/w...t=DSC00456.jpg

Thank you all for the replies. I will try and locate a ECM and give that a try. I'll post back on the results.