I recently got a pretty good deal on a 04 tl Automatic w 214k miles (this is my 2nd TL)
It has a cel for misfire in all cylinder and random misfire. It only misses on idle, and when I'm driving it runs and drives perfect with no issues, except on idle.

1st thing I checked were plugs, pulled the plugs and they are brand new, did some digging in the glove box and found they were replaced on 1-3-15

2nd I checked is coil packs. it seems when the engine is cold i can disconnect a coil pack and it doesnt have much effect on the engine. but when the engine is warm it effects it more? I ordered 3 new ones and they are on the way regardless.

My brothers friends own a tire shops where they do some mechanical work. he has some expensive snap on scanner and when it was plugged in it says that they are all missing but cylinder 5 & 6 are the worst. for example - They'll be at 10-12 misses where the other 4 are on 0-4 misses, ran to autozone and picked up one coil and put it in cylinder 4 and it seemed to make 4 run smoother as well as cylinder 1?

did a compression test and they checked out good. 180psi ~ 5 psi.

The person I bought the car from admitted to buying it for flipping it. told me the guy he bought it from is the original owner and the car has been sitting, going off this i ran the car till there was only 2 miles left on range and I put premium and some injector cleaner in it (does this stuff actually work?)

I saw on here people are mentioning updating firmware on the ecu? I called acura client relations as well as an acura service department and all the recalls were done but it doesnt seem the ecu update is a recall therefore they dont really know what im talking about. They keep saying valve adjustment which i dont believe is the problem.

Wondering what your guys' take is. im open for suggestions

 

Sounds like it needs a good 'ol seafoam treatment and a valve adjustment.

 

I'm already running an injector cleaner..