Fault Code - PO 300, 301, 302, 303 & 306

[marcesq]

Over 18 months of trouble free running of our '99 996 (127k on the clock), and today the car starts running like it has 2 cylinders rather than 6. Plugged in the reader and got the codes mentioned in the title. So thanks to the fault code listing on this site, I learned what I already knew . . . ie misfiring in cylinders 1, 2, 3 & 6.

I will start with the usual suspects this weekend and trouble shoot the ignition system.

I did not have the car running when I read the codes. Should I try that to see if I get a more precise indication of the problem??

Of course any and all thoughts are greatly appreciated.

TIA

Marc

Edited December 15, 2006 by marcesq

[Loren]

These could be damaging to the TWC if your CEL is flashing - so keep that in mind.

A car with a flashing CEL should not be run or driven.

Recent refueling? bad fuel?

Any recent work - like spark plug replacement?

If so, check for cracked coils or poorly connected cable/coils.

Any smoke from the exhaust - like oil burning?

[marcesq]

Recent refueling? bad fuel?

Any recent work - like spark plug replacement?

If so, check for cracked coils or poorly connected cable/coils.

Any smoke from the exhaust - like oil burning?

Thankyou.

Refueled right before problem, drove about 15 miles and then problem started.

No recent work

No oil, or anything else, coming from exhaust.

I didn't have time to work on it this weekend, but will start with replacing the fuel filter, then deal with a full tank of gas.

Cheers.

[marcesq]

Ok, it's been a long cold winter. Changed the fuel filter and drained the tank. Added 4 gallons of fresh gas and no change.

Symptoms . . . to start car pedal needs to be depressed about 1/2 way. The car will not idle. If the pedal is release it die after hard "chugging" for about 10 seconds. After starting if I keep the car over 3000 rpms it will keep running but not smoothly.

Any thoughts?? where I should start.

Thank you.

Marc