Tormod

Hello

My 99 Boxster 2,5 misfires when it is warm and the engine is idle. Codes p0300, 01, 02, 03, p1530, p1531, p1319, p1313. Not at the same time, but only when the engine is warm. When I drive normally, there are no misfires. But after been stopped for a red light the cel somtimes come on.

Anyone?

Tormod

Tormod

Macster

My 2002 Boxster would throw error codes, not misfire error codes, after the engine got warm, and at idle, and this was from what proved to be a leaking oil filler tube cap.

With the engine up to temp and idling see if you can move the cap around or even try to pull it up even though it is screwed tight to the filler tube and as you are doing this listen for any air leak or if the engine reacts.

I've worn out two oil filler tube caps over the years (14) and miles (>300K).

There is the good old MAF to suspect. I know misfires confined to one bank suggest an error condition that is not common to both banks, but I came upon a Boxster owner in the UK and his engine was misfiring on just one bank -- I forget the bank # -- and it proved to be a bad MAF.

A "test" is you can disconnect the MAF and road test the car and see if the bheavior is present and if not reconnect the MAF and see if the behavior comes back.

Not trying to get ahead of the game but if it does prove to be the MAF but be aware for the early models there was a MAF "upgrade" and a newer MAF is now specified but for this to work requires a FLASH update to the car's DME (engine controller). The newer part # MAF will not work right if this FLASH update is not applied.

You can still install a new MAF but it must have the same part # as the one you currently have. The problem is the older MAF with the same part # may no longer be avaiable.

While it doesn't necessarily read like a plugs/coils misfire problem I'll just mention that plugs may be due to be changed on miles and the coils too just because they are shot. I don't know where you are are but some regions of the world are really hard on coils on these cars. For instance, I was reading about misfires and bad coils in UK Boxsters long before I came upon the same posts on the USA forums.

And of course, O2 sensors have a finite life too. While they can last a long time, they do wear out and at differnt times. I'm having the ones in my 2002 Boxster replaced as I type and they have at least 200K miles on them. OTOH, the ones in my 2003 Turbo needed to be replaced at just 132K miles.

Last but not least, the early Boxsters have a serviceable fuel filter too, so you want to make sure that is not past its change by date.