delanobe

I would also clean the isv with motor cleaner until you can hear "clic clac" when you shake it.

I had the same problem and it was 100% solved with this.

Good luck!

Ryan360

Thanks again delanobe.

DaveK

How is your battery?

I took a (very) quick look at mine over the weekend - I started it up while logging with Durametric. There are actually not that many things I can monitor live on the 964 (much less than the 996) but I did monitor engine temp and voltage. Engine temp looked fine to me, but voltage was low - often reading 11.7-11.8v.

I don't know how accurate that reading was, but I know these cars don't like low voltage so I'm wondering if I have battery problems. I was told years ago my alternator output was below spec - I leave my car on trickle charge, but I have suspected for some time the charger might not be working. I'm going to pick up a new charger and see if that solves my problem.

Shamus964

Don't forget to check that the car will run on either coil also - disconnect each LOW VOLTAGE lead under the coils and make sure the engine will run on either. Mine had corrosion on one of the connections and wasn't working while cold.

Doug&Julie

Ryan, did you ever get this fixed? I'm having similar cold start issues and am curious what you ended up with.

Makmov

Mine did the same thing, real irradic idle and sometimes stalled.

I cleaned the ISV and it was rock soild for a week or so and now is starting surge +50 rpm at idle.

I think my control valve is iffy at best, some from before I got it has worked it over pretty well.

I also replace the O2 sensor, DME relay, reset DME, it idles and runs better but not quite perfect yet.

I am planning on Coils, ignitors, wires over the winter and it's due for a valve adjust.

Doug&Julie

I'm only having a cold start idle issue...the car wants to stall at first start up. Need to keep on the gas. 100 yards down the road and it's not an issue. Once warm works perfectly. I'm hoping I just need to clean the ISV...the one thing I didn't do when I had the shop in Indy do a 60k service. Oh, that and maybe a new O2 sensor. Everything else is new or newish.

Makmov

The other thing to look at is the micro switch. It just lets the DME know the throttle is closed all the way. so if you touch the gas peddle when starting it it confuses it.

Doug&Julie

Where is said micro switch? I don't touch the gas when I start the car. It takes a few extra cranks to start, then doesn't snap to proper idle, then dies. So then I crank it, get it to start, and keep giving it some gas until it's "warm". This only started happening this morning (but also happened at lunch), so by "warm" I mean until I back out of the garage / driveway and get about 100 feet down the street. I feel a slight hessitation when pulling away in low revs. Higher revs keep it smooth. Again, all of this only for the first hundred feet or so. Then it seems to operate smoothly.

Thanks for the help!

Makmov

engine end of the throttle cable. low on the driver side - back left side of the main intake body.

Doug&Julie

Thanks. What would I be looking for? ..sticking? ..need of cleaning? ..inop and needs replacing?

Thanks again.

Makmov

any and all of the above. you know the usual suspects.

Ryan360

Doug&Julie,

I apologize for not responding quicker. I've been out of town with no internet access. You may have already solved your dilemma, but to answer your question, I did get my idle issue fixed by adjusting the throttle/microswitch making it a bit richer. I also added a can of LubroMoly fuel injection system cleaner and 2 cans intake valve cleaner per mechanic's suggestion. I was very surprised that the idle does not hunt any longer. I also switch to Brad Penn synthetic (10w/40) from Mobile1. Overall the engine sounds great- at idle or on high RPM. In the future, I intend to replace the O2 sensor and the plug harness/wires. These are 2 items that have not been replaced for at least 40K miles according to my records. Good luck.

Ryan

p.s. I also cleaned out the throttle body for oil residue.

Unkle

Charge the battery fully, and i mean fully and then test it on the car that has sat for 5 days. I think you will be pleased with the results...

Get a charger that goes through the correct cycles. Desulphation, soft start, bulk, absorption, recondition, float. Then your car will start and idle great from start up after a week.

Doug&Julie

No problem. Thanks for the response!