Weird Idle
Thread Starter
On The Tree
Joined: Jan 2004
Posts: 196
Likes: 0
Weird Idle Ok, one day I was in the rain, and I was doing donuts, the next minute...my car was laggin when I pressed the Gas Pedal...I got my car scanned and it said the 02's were bad. So I replaced the 02's...and still the same thing...I replaced the Spark Plugs with AC Delco Rapidfires, and my MSD Wires are still in use. They have about 30,000 miles on them I think. So my car felt better after I replaced my 02's. I put on a LS6 Manifold, and I reset my PCM. It started runnning hard on the the Idle, but I heard it was normal for about 100 miles till it relearned itself. Welp, it hasn't fixed itself yet. I took it in to get scanned again, and it said TPS malfunction, Random misfire, and the rear 02's were missing, which they are cause I have LT headers. So I put a new TPS sensor on and reset the PCM again and it still runs very hard at Idle and the thing that bugs me the most is when I press the Gas Pedal, it LAAAAGGGS....and then it kicks in. It's the most annoying thing on the planet...it just lags for about a sec and then it kicks in...what's wrong with muh car? 
I expect your open-loop mixture is pretty out-of-whack and
you depend on closed loop to bring it around. This has a lag
to it. I would check that the manifold install didn't leave you
with a vacuum leak, first. You need to be able to see the
LTFTs and O2s.
A change in behavior that (maybe) is event-related might
have to do with something coming loose, O2 wire getting
burnt, etc. Have to do some inspecting over & under for
that kind of thing.
People will want to know what kind of stuff has been done
to the car in the way of bolt-ons that might affect mixture.
The signature is a good place to lay the cards on the table.
you depend on closed loop to bring it around. This has a lag
to it. I would check that the manifold install didn't leave you
with a vacuum leak, first. You need to be able to see the
LTFTs and O2s.
A change in behavior that (maybe) is event-related might
have to do with something coming loose, O2 wire getting
burnt, etc. Have to do some inspecting over & under for
that kind of thing.
People will want to know what kind of stuff has been done
to the car in the way of bolt-ons that might affect mixture.
The signature is a good place to lay the cards on the table.
Teching In
Joined: Dec 2001
Posts: 387
Likes: 0
From: Southern IN, USA
Are you currently throwing any codes? the IAC is a VERY carefuly calibrated beast, and it's easily damaged. Any chance of this? What about non-electrical issues - have you done a compression test, an injector test, etc.... What about maintenance?
You DID use rear O2 simms didn't you???
You DID use rear O2 simms didn't you???
Originally Posted by emarkay
Are you currently throwing any codes? the IAC is a VERY carefuly calibrated beast, and it's easily damaged. Any chance of this? What about non-electrical issues - have you done a compression test, an injector test, etc.... What about maintenance?
You DID use rear O2 simms didn't you???
You DID use rear O2 simms didn't you???
did you do the idle relearn procedure :dunno:
Teching In
Joined: Dec 2001
Posts: 387
Likes: 0
From: Southern IN, USA
That is correct, REAR simms are not necessary, but an unterminated connector can do many bad things in a low voltage environment....
Idle is done automatically after a few drive cycles if it is not done immediately after replacing power to PCM.
Keep us informed.
Idle is done automatically after a few drive cycles if it is not done immediately after replacing power to PCM.
Keep us informed.
Trending Topics
Originally Posted by emarkay
That is correct, REAR simms are not necessary, but an unterminated connector can do many bad things in a low voltage environment....
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On The Tree
Joined: Jan 2004
Posts: 196
Likes: 0
yeah....Ok, well the car is basically having a very rough idle, and I don't think I have a leak but my car doesn't really know how to Idle either...I DID however, clean the Throttle Body when I put the Intake on and I cleaned it with Carb. Cleaner and I didn't cover the sensors...could that be a problem? Other than that...it just has the rough Idle and lag when I press the gas pedal...
Originally Posted by SoloSport
no I haven't used it when the car is running, but I used it about 2 months ago...I'm just frustrated...
Originally Posted by SoloSport
soak it? Would it ruin the sensors? Anyways, jrp, I was looking at your double timing chain...what does that do? I like it...and our cars are almost set up exactly the same...
. its a good idea to install a new timing chain on a 98-00 car during a cam swap. i bought it for 75 bucks from TSP, and its adj. cant beat the price. and great insurance against breakage. you dont want a broken timing chain 
Thread Starter
On The Tree
Joined: Jan 2004
Posts: 196
Likes: 0
Ok yesterday I ordered the ICS...IAC ?? I don't know what it stands for but the long name for it is the Idle Control Solenoid....is this what the IAC represents? Anyways, I should be picking it up around 2pm California time....Anyone think It's a different sensor? Thanks.