Random Misfire

[318TIman]

Hi, I have a 1998 318TI that now has a random misfire. It started running real rough for about the first 2-4 minutes when starting cold. After the 2-4 minutes it runs like normal, but the check engine light stays on. I took it to my mechinic and he said it has a random misfire on the 2 and 3 cylinders. He checked the coils and said they are good, and the spark plugs are only about 6 months old. He put some fuel injector cleaner in the gas tank and said see if that fixes the problem. So far it has been about 5 days, and half a tank of gas with no improvement. Does anyone else have any suggestions? Thanks

[J!m]

That's a crazy one.

I would have done the same thing- checked the coils to see if they spark.

Wires OK?

It COULD be a clogged injector or two, and if the coils are in fact firing, that pretty much points to fuel, since it gets air. In tank cleaners are not so good. If you (or the former owner) use crappy gas, this can clog up the injectors. They may need to be removed for a proper cleaning, which typically calls for sending them off to a specialist. I think outright replacement MAY be cheaper, but not sure. Never had to replace them in a BMW this new.

Was it ever over-heated, where the head may have been damaged? I suspect not as it runs fine once warmed up. A compression / leakdown test may not be a bad idea...

That's the best I can do without having the vehicle to test myself.

[DinanTi]

Hey,

I had a miss fire not to long ago. I took it to my mechanic and I believe what he had told me was that I needed a new head gasket because there was oil leaking in and causing a miss fire. I not sure if what I said makes sense but replacing the head gasket solved my miss fire.

Scotty

[DinanTi]

Hey,

I had a miss fire not to long ago. I took it to my mechanic and I believe what he had told me was that I needed a new head gasket because there was oil leaking in and causing a miss fire. I not sure if what I said makes sense but replacing the head gasket solved my miss fire.

Scotty

[318TIman]

Today I pulled the spark plugs to check them. They are NGK with 4 electrodes. They all looked grayish. Since they are only about 6 months old, what would have caused them to go gray so fast? I am going to replace them today and see if that helps. Are NGK spark plugs with the 4 electrodes ok for a 1998 318TI?

I have owned the car about a year and only use 93 octain gas. The car has never overheated.

[318tibimmer]

I had some bosh +4 in my car for a while and then I started to have the same problem - I checked just cyln 1 and 4 and none of the rest, it said that I was having misfire on 1 and 4. They were ok, then a couple of days later I was like just for the heck of it lets go with a colder plug, just incase it was Detonating every so often. When I pulled out plugs 2 and 3 the electrode had totaly broken off. After I replaced it worked great. Let us know if the change helps you.

[1996 328ti]

Originally Posted by 318tibimmer

I had some bosh +4 in my car for a while and then I started to have the same problem - I checked just cyln 1 and 4 and none of the rest, it said that I was having misfire on 1 and 4. They were ok, then a couple of days later I was like just for the heck of it lets go with a colder plug, just incase it was Detonating every so often. When I pulled out plugs 2 and 3 the electrode had totaly broken off. After I replaced it worked great. Let us know if the change helps you.

It's funny that a lot of people think those 4 pronged plugs are good. I read more and more posts of them breaking off. I'll stick to the double posts that BMW recommends.

[318TIman]

Yesterday I replace the old spark plugs with Bosch platinum +4 spark plugs. This morning the car started up and ran good with no misfire noticed. I guess my new problem is why the old NGK plugs only lasted about 6 months. When I took them out they were gray and black looking. The car doesn't run hot, or leak or burn any oil or antifreeze. What else could be wrong with my car that would cause it to foul the plugs so fast? Thank you.

[2ndBimmer]

Funny then how NGKs were OE on these cars (mine at least).

[318tibimmer]

When they are the Dark Grey they are not really worn out, they have just been used. When I didn't have Nitrous, the Bosh +4 were great - But when I installed the kit I found that the +4 were to hot and was causing random detonation (Only when using the Nitrous, ( This will kill a Motor Quick)) So I changed to the Bosh +2 and now everything is fine. I replace My plugs every 6-8 months. So I am about in the same replacement time as you (even tho I probibly don't need to)

[m3rty98]

Ive always heard that NGK +4 are crap especially on turboed engines. just go with the stock plugs or just platinum.

[318TIman]

After about 3 days with new spark plugs my car is back to starting badly. It starts and runs rough for only about 3-4 minutes only when it is cold. If I start it when it is warm, it runs fine. I guess I will have to take it back to my machinic soon. Its weird how it runs fine after about 3-5 minutes, and how it ran good with new plugs for about 3 days.

[kurthansen]

If it was my car, I'd try installing a set of OEM Bosch plugs.
$.02

[ayton]

I had a problem with my car running rough a few weeks back...I had not driven the car for about a month and it had a full tank of gas, basically it was bad gas. I put in one bottle of cleaner and it ran ok for a day or two trying to burn it out....I eventually added another bottle when it started to drive me nuts and it cured the problem instantly. 2 bottles 1/2 tank but it has never come back again, I do have to change my plugs though and I have bosch platinum 4's but I have heard very mixed reviews about them in the ti? any suggestions people they are already bought so I may just try them