Cylinder misfire CEL in cold PART 3

[canis]

Hello all. I have an '05 LGT with about 50k miles. It has the Accessport Stage 1 and an aftermarket filter. The car got new NGK spark plugs about 10K miles and 6 months ago. It was fine all summer, but recently it got cold and the car threw a CEL for cylinder misfires on all four (0301, 0302, 0303, 0304). I reset the codes, and two days later it threw the CELs again. It happens first thing in the morning when the car is warming up, or when I'm on cruise control around 58mph.

 

I had the battery tested last week, and it was bad. Got a new battery, and the car was fine for a week. Then it threw codes again. I divorced the AP and took it to the dealer. They said it needs two new coils and it could use new plugs (I'm assuming they didn't check the plugs). They want around $500. I'm going to buy four new coils and four new spark plugs and do it myself, still for around $500, but I get all new coils. I'm going to change the spark plugs in case they were fouled during the couple months of bad coils.

[BoOCh_00_GT_Ltd]

possibly skewed coolant temp sensor or weakfuel pump for cold miss, and maybe a bad spot in your tps for 58mph miss

[JoeFromPA]

I'm guessing the coil packs are supposed to last longer than 60k miles, if they cost ~$125 a piece.

 

That's pretty damn expensive. Are you sure those are the source of your problem?

 

Joe

[coolbluelb]

I pulled the 0302 for the first time when the temp dropped into the 30's. Now it has done it regularly for a couple of days. will start with the plugs, I guess....