Ottawa964

Hi, I am new to Rennlist and this is my first post. I have a 964 C2 with an aftermarket exhaust (not sure of brand right now, but will check in the spring). It also has a hunting idle when warm. I had an engine reseal performed by Autoxtrem, who did a great job with the reseal and cleaned the idle control valve at the same time. The hunting idle continued, until I borrowed a stock exhaust to pass emissions. With the stock exhaust there is no hunting in the idle, it just stays rock-solid at 800.

My question is, is there something about the reduced back-pressure of the aftermarket exhaust that causes the hunting idle, or is there something else I am missing?

Thanks.

Vandit

Right off the bat, I don't really see a connection.

Can you give us more details on this aftermarket exhaust? Was it using stock components and just deleted the primary or secondary exhaust canisters? Did it retain the heat exchanger manifolds or had headers? Did it have a catalytic converter? Did it run an oxygen sensor?

Ottawa964

The car is in storage for the winter so I can't verify everything, but I understand there is one oxygen sensor, but the exhaust has a pipe on each side. No catalytic converters but retains the heat exchangers. Maybe the single oxygen sensor?

greg1990964

You need to get the car out of storage or wait and check very carefully for vacuum leaks. First thing I would check. Exhaust should not make a difference unless O2 sensor causing some of the hunting. These cars are very sensitive to vacuum issues. You can even hear the difference when you take off the oil cap while running.

MusicMadMike

I got my barn door MAF reconditioned and this sorted out the problem for me. My garage had a freshly reconditioned one on the shelf and bolted it on. The change was immediate and it flet like I was driving a different car. My old one was very tired, dirty, clogged up and in need of attention. I got it reconditioned and not only am I not hunting idle anymore my fuel economy has majorly improved and as mentioned earlier the car is super smooth and runs like a dream. I run a full Fabspeed header muffler setup and in conjunction with a SW chip and refurbed MAF I couldn't be happier.