97 STS Skipping....

[Gearheaad43]

I've got a weird skipping (missing ) which started a few days ago.... On idle, you can feel the car jerking slightly (Tach is dipping ) It is NOT noticeable under acceleration. It is worse if the AC is on and the car is idling.

No SES light.... No codes ...yet
New plugs & Wires

I'm wondering if this is a sign of a bad coil?


Anyone here have a problem like this?

[chubbyranger]

Originally Posted by Gearheaad43

I've got a weird skipping (missing ) which started a few days ago.

New plugs & Wires

I'm wondering if this is a sign of a bad coil?

I'd recheck the wires and plugs first. Lots of times new stuff and new problems go together. You can ohm out the wires to make sure they are all good and installed correctly. Can also pull the plugs and see if one is fouling which may lead you to a bad coil pack. Also check for vacuum lines that may have been disturbed when the plugs were done.

[Gearheaad43]

Plugs and wires were installed a couple months ago.. no problems...

Skipping started a couple days ago... very slight it first ... getting worse... Full Power is good, and from what I can tell, no missing under heavy throttle

[chubbyranger]

Then I'd go back to vacuum - my favorite place to start for low RPM skipping. Maybe the PCV?

[lbwd]

When one of my IGNITION COILS went bad, I would idle so rough and my car would die in reverse at slow speeds. Then even when I would accelerate, it'd still shake a little. If you car's not overheating, the ignition coils would be worth looking at as a possibility. I don't know how to tell, physically, if one is bad though. If it does overheat or sell like sulfur, we'd know it was the catalytic converter.

[Gearheaad43]

I changed the PCV at the same time I did the Plugs & wires.....

As far as testing the coils there is a spark tester you can buy at AutoZone that will indicate a weak coil... I may need to do that.... I just hope its not the ICM... .. BTW it's not overheating and nothing smells weird...

[Gearheaad43]

Update!..


Misfires finally getting bad.. Set the SES , got a P0300 code and that is ALL...

I'm really suspecting the ICM module board.......

BUT could a failing CKP set a P0300 code?

P.S. I hate generic codes.. P0300.. Sheesh.. OK what is causing the mis-fire.. about a dozen or so things I have to check......

[Ranger]

BUT could a failing CKP set a P0300 code?

I don't think so. It would set a CKP code or if it stalled, obviously a stall detected code.

There is a way to check the coils by checking the ohms but I don't remember what they should read. Might try listening to them with a stethoscope and see if you hear any arcing or swap them out one by one with a known good one (that's how I eliminated them when I had a misfire on my '97).

[Gearheaad43]

Originally Posted by Ranger

I don't think so. It would set a CKP code or if it stalled, obviously a stall detected code.

There is a way to check the coils by checking the ohms but I don't remember what they should read. Might try listening to them with a stethoscope and see if you hear any arcing or swap them out one by one with a known good one (that's how I eliminated them when I had a misfire on my '97).

ok.. Thanks,,, Looks like I'll have to my adjustable ignition spark tester to use here.....

[Gearheaad43]

Update:

Well guys, I've MISPLACED my ignition spark tester , So I took the entire ICM / Coil pack assembly to AutoZone for testing. They could not test the ICM cuz of lack of an adaptor to fit the NorthStar's 4 bay ICM..... ICM is 280 something with lifetime warranty.


So... I told them to test the coils... The 2 & 5 coil registered "0" on the ohmeter.....Ahhhh BINGO!!! Also discovered a crimp in the No-2 plug wire that got "pinched" between the engine cover bracket and the cover near the passenger front cover bolt.. That must have been arcing, which is what caused the 2-5 coil to short out.... Got all that fixed .... running smooth again, then 10 mintues into the check all systems test drive... The passenger rear tire blows out at 75 MPH.........

Still dealing with this crap this morning...

Heck wish me luck guys....

[Gearheaad43]

Caught a roofing nail on the interstate...... $150.00 +$45.00 bucks later I got a new P225/60R16 Michelin XGV4 Plus H rated tire mounted, balanced and back on the STS... (Matches the other 3) Good to go.... I'd like to see how much more money that car is going to cost me this week........

[rockybalboa11]

i've got the same symptoms on a '94 sts

polo green funny enough :-D

[Gearheaad43]

Originally Posted by rockybalboa11

i've got the same symptoms on a '94 sts

polo green funny enough :-D

Check for bad coils

[rockybalboa11]

taking it to the dealership on friday morning

tired of having other mechanics throw parts at the car & not fix anything

[digitalcaddie]

I had the same problem on my '97 SLS w/ the same P0300 code. I tried one new coil pack in each of the four spots but that didn't fix the problem. So rather than getting one more new coil and playing musical chairs trying combinations of two assuming two coils were burned up, I just got 3 more new ones and put those in. That didn't fix my problem either though. So I took the new coils back to Autozone and decided to take a look at plugs. I pulled one plug this morning and it looked pretty shot so I went and got 8 new 41-950 Delcos and am planning on installing those this afternoon. I'll post the results.

Unfortunately for me coil packs did not fix the problem...those are much easier to change than the plugs.