high revving and check engine light
 

Hello All,

I finally got my 91 C2 cab out on the road for the season last weekend. The Porsche was running flawless and I really got into it. I had a aggressive take off from a stop and I think I over reved it. The exhaust note changed and the car was now very loud.

I got it home and turned it off and ten restarted it, now the check engine light was illuminated. I took a look at the exhaust and noticed that the had come disconnected at the junction of the left sided intake of the rear muffler, which explains the loud exhaust note, but I am puzzled by the high idle the car now has....

Any ideas or suggestions? I have yet to reattach the muffler.

With the huge exhaust leak, you have an extreme lean condition as sensed by the O2 sensor. Fix the muffler issue with a new gasket, and I suspect your troubles will subside.

exhaust fixed, still high idle
 

I have fixed the exhaust and everything is tight. Still the check engine light is on and the car idles at 3000 rpm.

What next?

Try disconnecting battery , wait about twenty minutes...a long shot but it is easy, cheap and may work

Check all the rubber couplings on the intake plenum to make sure nothing popped out of place. Look at the throttle cable and make sure the throttle body is resting on the idle switch.

Thanks for the ideas, will try them later today and report back.

all good
 

I checked the throttle linkage and the cruise control cable. They all seemed fine. I disconnected the battery overnight. Reconnected everything this morning and all is well again. Great day of motoring.

Many thanks to everyone.