Aggressive Driving CEL

[DamageINC123]

Gentlemen,

I am new to the forum and would appreciate any advice you guys may have. I have a 97 with 30,000 miles. It runs perfect all day long but when I start driving aggressive (tach around 6,000) the CEL comes on. The code was a misfire left bank 1 & 3 if I am not mistaken. All service have been completed by Porsche since day one. The Porsche dealer thought it was the airflow sensor so I replaced it. Porsche checked the hoses on the emmissions but did not find anything. I will say that the air pump can be heard on cold starts. It seems to be as little loud but I have nothing to compare it to. Any help or suggestions would be appreciated. Thanks in advance.

[Adam]

Have the plugs been changed? The air pump being audible is normal. Did this just start or has it been going on awhile. Maybe just a tank of bad gas?

[DamageINC123]

Thanks for responding. I am on 3rd tank since problem started. Plugs were replaced last year with 30,000 mile tune up by Porsche.
I am wondering if I have an intake leak. Maybe the computer is compensating for the leak until high RPMs are reached. Although it idles perfect and revs great.

[Adam]

Mmmm... I don't think it be an air leak on the intake side, because that would usually cause a hunting idle and roughness throughout the powerband like you thought but it wouldn't hurt to have a vacuum leak test done. Maybe have the coil packs inspected on banks 1 & 3 and while you're in there inspect the plugs and see how they look.

[DamageINC123]

The techs had mentioned doing that but after the MAS was cleaned the problem temporarily went away and the coil packs were never checked. I will check them out.
I do have aslight vibration at high RPMS. Its only noticed with the top up. The techs that test drove it did not mention the vibration. However its responsive under throttle and and idle is perfect.

Lets say I do have an intake leak. Do you know about what the cost would be to correct?

[Bladecutter]

I would recommend trying two things before blaming it on an air leak, and will help determine if its a coil pack issue, or an oxygen sensor issue, or even possibly a clogged fuel injector issue, as 30k miles on a 97 might have lead to clogged injectors from lack of use.

Start with the most simple thing:

Dump a bottle of Chevron Techron Fuel System Cleaner in with your next full tank of gas. That might help clear out some minor fuel clogging issues.

Next up is to remove the coil packs from each cylinder, and swap them from the left bank to the right bank. If the problem is with the coil packs, it will follow them to the other bank.

After that, I would swap the oxygen sensors from the left exhaust to the right exhaust. If the problem is with the oxygen sensors, then it will follow them.

I recommend doing these one step at a time, and wait a week before doing the next item. If you are good with working on cars, you can do all of this yourself, because its all easy stuff to do.

BC.

[DamageINC123]

Thanks for th info. I actually put a bottle of techron fuel cleaner in last night. I will run that through before I swap the coil packs. Is the drivers side 1-3 or the passenger side? If i remember correctly Porsche said left bank 1 & 3 (1-3) misfire
Also can Advanced Auto read the codes for me or do I need to take it back to Porsche?
One last question. Where can i buy a code reader?

[vath2001]

A couple of options for a code reader : Amazon for about $80 for an Actron (works on all cars) or go for the $300 Duritech system that will read everything Porsche.

Advance Auto should be able to read the codes. They may have a code reader for sale too. Write down the code numbers and bring them back. Or go to Renntech to look them up

[Steve Tinker]

Right hand side (passenger in US) - cylinders 1 (F), 2, 3 (R).

Left hand side (drivers in US) - cylinders 4 (F), 5, 6 (R).

I bought a Duratech code reader - excellent service and product......

[DamageINC123]

Thanks Guys for all the help. I appreciate everything and will keep you posted.