Mark Wiebz

I am at my wits end. I had the ABS, PSM , and occasionally a CEL. I would clear them but the ABS and PSM would come back instantly the CEL after a few miles. I replaced the brake switch last week. Did nothing. Researched and found it may be the MAF sensor. So, I replaced that and a new air filter because it was black and greasy. Now I have no warning lights but it runs very rough. What to do now? GRRRRR!

DBJoe996

Running rough? New MAF. Disconnect the battery for 15 minutes to reset the DME/ECU. If you have E-gas, do a calibration. Then go for a steady drive to have the DME reset the initial values.

wyovino

Is it an OEM MAF or a cheaper version? I've read, but can't confirm, that the cheaper ones can be bad and that some can be installed backwards.

Mark Wiebz

It is a Delphi. So, it's not a cheap one. It only goes in one way.

Imo000

Have it scanned during a test drive and see what the numbers show. Without any real data your guess is good as mine. If you don't do this, it will get expensive.

Mark Wiebz

I'll try that! Good idea. What is E gas? Ethanol? I usually run Shell V-power 93 octane. Getting into new territory for me. I have no idea about calibration.

strathconaman

If you have an electronic throttle, e-gas calibration (or throttle adaptation) is performed by:

1. Switch the ignition on for 1 minute without starting the engine.
Do not actuate the accelerator pedal (for instance, make sure
that there is not a carpet pressing on the pedal).
2. Switch off ignition for at least 10 seconds.
3. Switch on ignition. You should hear some "clicking" from the engine compartment as the computer adjusts the throttle

The following conditions must also be observed, otherwise learning
is not possible:

♦Vehicle is stationary
♦Battery positive voltage between 10 V and 16 V
♦Engine temperature between 5 °C and 100 °C
♦Intake air temperature between 10 °C and 100 °C

However, a "black and greasy" air filter doesn't sound good. If you remove the rubber hose that goes from the airbox to the throttle body, look at the throttle body and make sure it isn't covered in oil. While you are there, clean the throttle body.

lowpue

i think he means electronic throttle vs cable throttle which depends on year of car. later cars were e-gas

Mark Wiebz

Thank you . I will try it.

Mark Wiebz

Probably not my car then? Mine is a 2002 C4

Optionman1

"The 1999 model was the only 996 to have a throttle cable connecting the gas pedal to the engine — perhaps a desirable feature for some shoppers. Go with a 2000 model or later and you’re treated to e-gas, and possibly Porsche Stability Management (PSM) on cars so optioned."

bull3t

Yours is drive by wire

808Bill

What type of Air intake are you using, stock or K&N?

Mark Wiebz

Had a K&N. Went to get a new one and they had an eldebrock one very similar shiney red and chrome for a couple dollars more .

wildbilly32

K&N...or most any oiled filter belongs only on a race car which gets serviced after every race or lawnmower in my opinion. Seems counterintuitive to me to disable a true cold air intake(the snorkel) and put an oiled filter in the hot engine room then try to block said filter off from the heat with walls. This doesn't take into account the maintenance nightmare of the oiled filter and what can happened if serviced incorrectly. I don't get it! Must be the 20 h.p. gain the manufacturers claim...RIGHT!