BoxsterC

I am new to this forum and am hoping someone can provide information to help me.

My 2005 Boxster S engine service light came up several weeks ago and was running rough and could not go very fast (<50mph). After I stopped after ~5 miles, I was able to restart engine and it ran smoothly without engine light lit.

Since then, I was able to drive it multiple times commuting to work (~20 miles each way) without any issue or engine service light lit.

Couple of days ago, I turned on engine and the engine service light was lit again. I turned off the engine and restarted hoping the service light would go away. Well it did not. I decided not to drive it in this condition.

I borrowed an OBDII reader from a co-worker and it showed P0304 (misfire w/cylinder 4). I cleared the fault code and attempted to start engine. The engine will crank, but it would not start even though it sounded like that some cylinder fired. Not enough to get the engine going though.

My questions are:

1. Can a misfire lead to severe engine damage in my case, since I drove it for ~ 5 miles with rough engine operation? I saw some minor coolant leak near the oil pump location. Did I crack the engine?
2. Why couldn't I start engine now?
3. Any suggestion with diagnosing and repairing this issue? I know I need to exam the spark plugs, and coils.

Any help is greatly appreciated.

Edgy01

Perhaps directing this to the Boxster (987 forum) will get you better answers! Tell them things like whether the car has had regular servicing, like new plugs at 6 years...

997_rich

I think you should be in the boxster forum- this is the 911 997 forum.

but no, I don't think a misfire could crack an engine cylinder or head. A misfire is a symtom of another problem, like a bad coil, failed fuel pump, valve issue.

The coolant leak is another symptom (of the same problem?).

I think we need more info to narrow in on your problem. Did you lose a lot of coolant? how much is left in the tank? when the check engine light came on did the car show overheat on the temp gauge? Does the engine crank normally? the only code that was thrown was a misfire code? How much gas do you have? Is it possible you got bad gas? open the trunk, turn the ignition key, can you hear the fuel pump working?

BoxsterC

Oops, I place this thread in a wrong place. Sorry. How do I redirect a thread to another forum. I know some forums don't like people to post same thread on multiple discussion groups.

P0304 was the only fault code downloaded.

The coolant level is normal and I don't see any sign of coolant on the floor either. I have full tank of gas when I tried to start. When the engine light came up, I did not see any sign of overheating on the gauge. The car seems to crank fine.

I was able to start and drive the car two days ago around the block when I decided to pull it back to garage.

What does it mean "bad gas"? I mostly fill up at Costco with premium grade (93 octane).

It is common to see misfire with Porsche engine? I bought this car used just 5 months ago; hence, I don't have a good history of its service record, specifically, I don't know when the spark plugs were last changed. My PPI record showed this car in great condition, but the shop did not perform compression test. This car runs great up to this point.

utkinpol

misfires are not commonm, of course, so you need to identify the source.
disconnect battery, then disconnect MAF sensor, then i would get to spark plug coils and first swap coils from one bank to other bank. then after you try to start - look if CEL code will show different cylinder or not. if it moves with coils/spark plugs as you move them around - then it is obvious what to replace.

if not - then you`ll need somebody to help you.

you can start engine with disconnected MAF sensor and drive car with it been disconnected. if issue returns after you connect MAF back - then wash it first then replace it if it will not help.