low rpms 2800 max

[wang]

1999 Boxster - trip - 37,500 miles

Max rpm 2800 - runs rough when cold - backfires - codes p0150,300,304,305,306,1317,1318.

Top speed about 35 mph. Had the plugs changed last weds - ok til this AM.

Thanks for your advice.

Wang

[Glyn]

unplug your MAF then run the engine - This could be the issue, if works OK unplugged get a new Maf, whilst unplugged the engine will run on its limited operational strategy

[mikefocke]

The codes translate to a O2 sensor short and a bunch of misfires...all on the same side.

So the MAF which would affect both sides makes no sense.

I'd look at the seating of the O2 sensor wires on the driver's side of a US car. Bet it got jiggled when the plugs were changed. Other possibility is plug wires into wrong cylinders but that would show up immediately and this didn't show up till later per your post.

[wang]

Mike

Thanks for your help. I think I will have it towed to the dealer in Reno - 50 miles.

Ouch $. Due to medical conditions I'm unable to do even simple work.

At least I have some info while talking with the salesman-service adviser.

Again thank you - enjoy reading your diy articles.

I will keep you posted.

Bob