: 97 eldorado w/180,000 miles, should i upgrade to a preformance coil?

07-08-09, 10:39 PM
i just got the car and it looks like nobody had done any routine maintenance in quite a while:mad:. it was real slugish when i first got it, but after replacing the air filter with a kn/like setup, plugs/iridium, and ignition wires it has really livened the car up. when i was replacing the spark plug wires, i noticed a lot of corrosion on the coil tips. so now i wanna replace the coil. i am gettin a lot of codes intermittently p0101, p0139, p0174 and p0300(alreadly looked them up on the forum and got a plan:-). these codes may or may not be related to the coil, but i was wondering what kind of preformance upgrade, i could get if i went with a preformance coil?

07-09-09, 08:21 AM
Use ACDelco coils, ACDelco #41-950 Platinum plugs, and ACDelco wire sets. Northstars do NOT like iridium plugs and aftermarket wires. The P0300 (miss detected) is probably due to the plugs or wire hookup

Do a LOT of reading in here, Electrical, and Seville/Eldorado if you don't believe me.

Make very sure the coil/plug wires are hooked up exactly as pictured, and that the coil connections at the ICM are clean and tight.

Google "waste spark ignition" for an explanation of why your system fires two spark plugs at the same time and why the coil/wire polarity for each plug is critical.

You accomplished nothing with the new air filter setup. Maybe even begin to set new fuel mixture codes. The other 3 P codes - MAF performance and O2 sensor operation - are due to your air intake duct changes. If you messed with the MAF (honeycomb screen ?) you're out a couple hundred bucks. That will eventually set a SES light and the car will fail emissions as well as maybe default to a fixed ignition "limp home" mode. That's all in here, too.

You will get no performance upgrade whatsoever by changing to aftermarket coils. Have the coils tested, and if one is bad, replace it. With your join date you should know all this by heart.