: 94 STS bogging and stalling?



Sean McDonald
08-17-04, 07:55 PM
Hey guys, kinda stumped on this one. When I decelerate and stop lately, my car likes to drop RPM's as as far down as approx 500 then shoot up to about 1200 giving me a slight surge forward then settles down. Now today on 2 occasions it bogged low enough that it stalled! Anyone know what could be causing this??

Thanks,
Sean

foo
08-17-04, 08:50 PM
http://www.cadillacforums.com/forums/showthread.php?t=16763&highlight=ISC

read that, maybe it will help :)

Sean McDonald
08-17-04, 09:37 PM
Thanks Foo! But I think my problem is a bit different.

foo
08-17-04, 10:12 PM
the ISC or the EGR failing all of a sudden would cause this.
Was it a sudden thing?
Oh yea and the question
ARE THERE ANY CODES???????? :)

Sean McDonald
08-18-04, 08:38 AM
It did develop rather quickly. No codes that I know of though.

foo
08-18-04, 03:18 PM
If it stalls it must generate a code.. push the buttons and check the codes.. i think it's the off and warmer buttons on yours but i'm not sure.. check the posts to see what buttons to hold down to get the diagnostic screen on yours

Aurora By Olds
08-20-04, 09:23 AM
Sounds like the ISC to me....
The '94 OBD I wont throw any codes for this usually.

Sean McDonald
08-20-04, 04:55 PM
Isc??

gorky
08-23-04, 11:59 PM
you wont believe this probably.

cause i didnt when it fixxed my problem.

but i had idling problems and surging like you described.

i took it in, but no codes and they couldnt duplicate symptoms.

sometimes it would stumble while starting to climb a hill.

anyway, it turned out to be spark splug wires and plugs.

new wires fixxed the problem initially, which just blew me away. i never thought wires could go bad period.

then a little later, started seeing similar problems. changed the platinum OEM plugs to copper tipped Autolites, at the suggestion of the auto parts clerk and havent had a problem since. very responsive and no stumble. he said i will have to clean and regap them every 12,000-15,000 miles but the old copper tipped units produce a "hotter" and more consistent spark.

BeelzeBob
08-24-04, 08:38 AM
changed the platinum OEM plugs to copper tipped Autolites, at the suggestion of the auto parts clerk and havent had a problem since. very responsive and no stumble. he said i will have to clean and regap them every 12,000-15,000 miles but the old copper tipped units produce a "hotter" and more consistent spark.



Obviously the auto parts clerk was "selling" Autolite plugs......LOL.

The OEM dual platinum plugs are far far superior to the Autolite plugs. The "copper" plugs will not make a "hotter" spark. No reason for it. The spark is the spark regardless of the material of the electrodes.

The dual platinum plugs allow for nearly unlimited mileage accumulation as the platinum does not disappear or wear at the spark interface. There is absolutely no way a copper spark plug can match that performance. Most of the OEM dual platinum plugs will run for at least 100K with no maintenance or service and generally they will run much longer than that even. If a dual platinum plug is causing a problem then I would look at the electrode for cracks induced during installation, the wrong gap or possibly a missing platinum pad on one of the electrodes. Otherwise, the OEM dual platinum plugs are nearly bulletproof and offer the best power to boot.

If the Autolite plugs you put in improved performance or engine stability then there was something else wrong that you fixed in the process. It wasn't the different style of plugs. The OEM dual platinum plugs have shown time and time again to be the best plug for the Northstar engine in owner comparisions and on dyno testing for power and durability.

Autolite replacement plugs for the Northstar engine are actually questionable for the correct heat range for the engine as I have personally seen a Northstar engine destroyed by spark plug induced preignition with Autolite plugs. The owner had run the engine at heavy loads for hundreds of hours with the OEM dual platinum plugs when he changed to Autolites to "see" what would happen. The engine was destroyed on the next full load cycle due to the plugs overtemping and causing preignition. Nothing was changed but the spark plugs and all of the plugs showed signs of preignition damage in addition to the piston with a hole in it. Be carefull if you are using Autolite plugs.

I would NEVER recommend Autolite plugs.