The other day I noticed that when Im slowing down and the rpm's are dropping, the tend to stick right at 1500rpm's for about 5 seconds then they drop down to 1000. Sometimes it does this right when I start my car. The needle will go up to 1500rpm's and just sit there for a few seconds then drop down. You can actually here my car idleing louder while this is happening then it get quieter when it drops back to 1000 rpms. Any suggestions on what this could be?

 

your pcm is doing that. I think it is supposed to do that to keep your rpms up for vaccum ran stuff like your brakes. I read a thread on here about this. It keeps it about 1500 RPM until you are just about stopped.

Jason

 

It has nothing to do with the PCM.

My car did that quite often when i got my new throttle body on. Ur throttle linkage is binding a little. I would recommend replacing it, but in the mean time i would just spray a little wd-40 on the linkage spring on the throttle body.

 

its normal... Don't look for problems, or you'll spend too much money like I do. Once you car comes to a stop it should drop back to idling range. The reason it does this is like the other guy said, its to keep vacuum pressure up to control the brakes. Your car's smarter than you think!

 

Thanks alot guys. I didnt think it was anything major, but I just wanted to make sure.

 

Mine was actually sticking in all sorts of places last night. When I tapped the dash it would go down to idling range. If I hit it, the needle bearly moved or had lag, same when it was idling down it just started sticking in places for awhile. But after I left again, it seemed to be working fine again. Anyone know what would cause that

 

arent you the guy in s.ville. i heard your car has never seen the track, how did get your times? estimating huh

mustang man

 

Uh oh, not another one. Who are you riceeater? How do you know me?

 

Try cleaning the IAC valve and it's passages in the throttle body. The valve may be sticking or there may be gunk in there that is causing poor operation.

 

Shoebox, do you think this would help my problem? I think it to be IAC valve related. Mornings my car starts fine, but idles ROUGH!! Runs RICH!! This clears up once operating temperature is obtained. But before that, it'll stumble and cut off.

Thanks

DJ

 

well i dont know you. but you must be the guy my friends were talking about. they said a guy in sville with a red and white camaro was supposed to race a cobra and he didnt show up. they said the car had never been to the track.

i was just asking but you answered my question. unless you have been to the track then i am wrong.

 

It IS the engine computer doing it. Mine has always done it. You can program it out if you have TunerCat or Lt1Edit. I have TunerCat and changed all the values in the "Throttle Follower IAC Offset Vs. MPH" to 3 and this eliminated it. The PCM is programed to "hang" the throttle until you come to a stop.

I have had no driveability issues in doing this. When I let off the throttle and push in the clutch, the rpms drop to 900, no matter what speed I am going.

Brent

 

Yeah the guy with the cobra was talking about racing.

I have a child at home and I just cant leave and go race with the boys whenever someone says lets go. Ill see him around soon enough and we can see how fast it is. He raced one of my friends and thinks he won because he jumped him by about 4 car lengths then my freind walked him down after they were going 120mph. If they would have hit it side by side my buddies car wouldve won easily.

Anyways, not trying to get this started again. The last couple threads got real nasty about this topic.

 

Obviously I'm not shoebox, he proly hasn't responded yet cause he's like normal people and actually sleeps. Unlike me. But anyway. Yes I believe your problem could be IAC related but that depends. Does the car idle low when it stumbles, or is it normal. If its low, then its proly the IAC sticking until it warms up. But, that shouldn't cause you car to run rich. If the rpm's are VERY low then it could. But you may want to look more along the lines of Oxygen Sensors. The whole point of these doohickeys is to tell the computer whats coming out of the combustion chamber. So if they are gunked up, then they could be giving a false reading until the engine warms up and goes in open loop mode (or is it closed loop) I don't know I'm really tired. But that most likely your best route to go. It never hurts to replace them. Anyway, have a good night, or wait morning!

 

Actually, the rpm's never drop below 1000 and never stick anywhere but 1500. I havent tried to clean around the TB yet, but I probably will after all the snow clears.