Misfire... only when cold. Where to start?

[suspenceful]

I bought my 2008 135i (N54) a little over a month ago. I traveled 6 hours to check it out and it was already warmed up when I test drove it. Everything was great and I took her 6 hours back home without a problem.

The next morning, I started her up and there was a misfire once I started driving. The colder it is, the worse the misfire is. Either way, after a minute or two of driving, it disappears. One time it was bad enough to throw the SES light for multiple random misfires. The light went away 2 days later. It doesn't seem to just be on 1 cylinder, but I could be wrong.

On a warm day, it won't misfire at all. But at nighttime or early mornings that are cooler, it will happen. The car has 84k and I thought it could be the intake valves, so I got them blasted. The car is a little smoother, but the misfire is still there. The previous owner said he replaced the plugs not too long before I bought it. What should I do?

[Dackelone]

Start by reading for codes. Could be plugs/coil packs/injectors.

[Garabins]

Originally Posted by Dackelone

Start by reading for codes. Could be plugs/coil packs/injectors.

X2

I had the same issues you are having. Read the codes to find out what cylinder is misfiring. Then replace the plugs. If it’s still misfiring, try moving the coil pack around to see if the misfire follows the coil or if it stays on that cylinder...If it’s not the plugs, coils, then it’s your injectors. I just went through the same process and ended up replacing all 6 injectors myself..

[rocketpop]

Same thing just happen to me but I lost two injectors, I ended up replacing just the 1 bank of injectors for now. Now I have 3 new ones and 3 older ones. Just waiting on the other shoe to drop. LOL

[..]

How many miles do you have? It would be a good idea to replace all spark plugs for peace of mind.