HUNTING IDLE and CEL problem
 

Hi Folks,

Recently noticed CEL on and that my 2000 S would have a fluctuating idle (about 500 rpm) every-so-often when I came to a dead stop. Being a diligent reader I've tried nearly everything suggested in the forums past posts about similar problems so far. I started with a fuel injector cleaner (Techron), disconnected/reconnected the battery to clear the CEL and ran it for a few days. No real loss of performance or anything, but idle still persistent and, as anticipated, CEL came back on a few days later. Then tried plugged it into an OBD II reader and got the following fault codes - p1198 and p1130. I went ahead and changed all four O2 sensors and this time used the OBD II to clear CEL. Problem seemed better, but came back a few days later (along with the CEL). Gave up, went to dealer. They ran it through the PST (II?) and I was told it was that the "Vaccuum Canister" needed replacing (along with a few other things they always seem to find at the dealers). As I was happily driving the car home (though with a much lighter wallet) I noticed (of course) that the idle would fluctuate every-so-often when I came to a dead stop. Any ideas?

There are really only a few more causes I can think of.

1) Bad/dirty MAF sensor
2) Problem with the idle control valve sticking
3) Vacuum leak in one of the hoses or covers

Some people have cleaned the MAF with brake cleaner successfully. If you try to do this, do not touch the metal connecting prongs unless you are in a static-free environment. You can blow the circuit board that's inside it if you send a static charge into the prongs. Hopefully somebody else can tell you how they sprayed the brake cleaner on the MAF.

I had a slightly more severe problem that led to my MAF getting replaced.
My fault codes were
P1130 Oxygen sensing adaptation, idle range, bank 2
P1128 .. bank 1
P1126 Oxygen sensing adaptation, lower load range, bank 1
P1133, ... bank 2

And the driving dynamis were that the idle seemed okay, but
1) at 3,000 rpm the engine sputtered, but accelerate through it and its okay.
2) One time, nearly all power was lost and the engine sputtered continuously, I limped to the side of the road. Shut off and restart, and the car came back to life just fine.

Replaced the MAF under warranty and all is well.

- X

Thanks for the feedback
 

Thanks for the feedback.
I did change out the MAF about a year ago, but will look into that also. I agree it may be the most likely candidate at this point....