1998 996 tip Engine ? problem

[Harry Alan]

Two problems which may be connected

1) Car starts first couple of turns most of the time.......then sometimes wont start for 5 or 6 seconds of churning.....doesnt seem to matter if its hot or cold......

 

2) at low revs ( below 2300) the engine seems to "hunt" and revs up and down about 200 rpm. It makes it very uncomfortable in traffic.

Had it tested static and driving and no fault codes for either problem.

Any suggestions much appreciated.

[Loren]

 

Have you removed and cleaned your throttle body?

This needs to be done probably yearly.

Also, carefully remove the cold start valve (do not lose the paper gasket - or replace if damaged) and clean it so it moves freely.

[DBJoe996]

Remove and clean the MAF sensor with MAF cleaner (since you will have the air filter box out anyway)

Remove and clean the entire TB

Remove the ICV (Idle Control Valve) from the TB and clean  it out with alcohol and q-tips, cycle it with a 9V battery to ensure smooth operation of the valve, it should not stick and should cycle smoothly, it should be shiny clean inside, not black (the is the usual culprit for "hunting idle"), as stated be very careful with the paper gasket, it is very fragile

Remove the TPS (throttle position sensor) and clean it up as necessary

Suggest replacing the TB O-ring upon reassembly