Well, im lost...

I replaced my throttle body, and have been driving normal, and suddenly my idle is going crazy every once and a while.

Sometimes ill be coming to a stop, ill hit the clutch, and my car revs up to 2k, and then either drops to around 1k, or, as was the case today, almost dies completely. I had to tap the gas to keep it running.

Anyone got any ideas on what is causing this? Im lost as I cant find anything. No codes are being thrown or anything, and under normal driving my idle will act fairly normal...well...for my car at least.

I had a full ECU reset (car was unplugged for 2 weeks), and my ECU has adjusted for the lower TPS sensor voltage of .93 (i cant adjust the damn thing so I dont know if thats it), and has been running normal, but I have no clue why my idle is acting stupid.

Anyone? Ideas? Im fresh out of them. Maybe run another can of seafoam through the car?

 

Seafoam wont help with a problem like that. Its probably something small though. Have you gone completely over the motor to make sure there arent any loose connections or something may not be plugged in? Sounds like maybe a vaccum leak to me. Get under the hood and listen for whistling noises or feel any air leaking. Also check you EGR valve. Sometimes those go bad and causes problems like what your having.

 

I dont know bout the 4v cars, but my tps is set at about .99 or 1.00, so see if you can somehow get it up, there isnt any way to adjust it other than moving it around until it is at .99 and then tighten it in that exact position. That is what Id say.

 

I changed the throttle body to a accufab single bore from a twin bore, and there is a whistle when I hit the accelerator, but after trying to track it down we figured out that the whistle is coming from my K&N air filter, since I just cleaned that. I cant seem to find any other point where a vacuum leak might be. I did take off my entire intake, upper and lower to clean my IMRC's, but I dont think I missed anything...

Humm...

Any easy way to check for a vacuum leak?

 

Drop you car in the lake...lol oh wait, no thats holes. Hmm. Not really an easy way, just start checking hoses I guess.

 

I've heard to spray brake cleaner over the engine bay until you see the RPM's drop. Once the rpms drop, you know around the area where your leak is.

 

Hmm, interesting, never heard it, but as long as its not fluid, why not right?

 

You are correct, but i use carburetor cleaner. , and your rpms will not drop, you will see a spike in the rpms momentarily.

 

How loud is the whistle you hear coming from the air filter? I installed a C&L plenum and 75mm throttle body on my 03 GT and had a whistle also....the problem was the IAC gasket wasn't lined up perfectly. Once I got it on better it was fine.

Also, .93 volts seems pretty low, but I don't know about 4 valves. I hooked my predator up and monitored the voltage after adjusting it a little bit. I didn't quite understand how to adjust it at first, but the voltage would change when tightening and loosening the two screws on the TPS. So I got the two screws on tight enough and then would back off or tighten them just a tiny bit and that would change the TPS voltage and ending up getting it to .99 volts. Not sure if any of this helps, but it doesn't take much to throw everything off.

 

I think it may be the TPS. Have you replaced that? I have a few I can send you to try.

 

Sounds like the IAC is bad. Clean it first to see if that helps. Or, just buy a new one, they're cheap.

 

Chris, I have a bunch of TPS's and one brand new IAC still int he box. If you want to try them before dropping coin let me know and I can send them to you. Then, if they work, you can get what you need and send mine back.

 

Blake is the man...seriously I dont know very many people that goes out of their way as much as he does.

 

I know its not the TPS, I just bought a fresh one from Ford. In talking to Randy, he said that anything between .9 and 1 is good. Plus my ECU was off for 2 weeks, so the ECU should have accounted for the new TPS voltage.

Randy thinks that its my IAC just gummed up w/ Carbon buildup (cold weather isnt helping), and that my PCV valve is ****. I bought a Pep-Boys PCV and he thinks that might be the culprit in this, letting too much exhaust back into the intake causing the idle to be all funky. I might run another can of Seafoam just cause, my engine couldnt hurt from it. Plus im also considering putting an oil-separater in my PCV line, because in taking my PCV valve off tonight, I saw a bit more liquid than I would have liked to. I have to run down to Liberty Ford tomorrow to get ye olde chin spoilers...so I should be able to get a fresh PCV valve and, judging how the car drives tomorrow, I can find out whether or not I need a new IAC as well.

Damn these simple things and cold weather.

 

to find vacume and intake leaks you take a propane blowtorch and open the valve and move it all around the intake and what not and if there is a leak the propane will choke the motor and it will die...fix it and problem solved...glad i could help...

 

my car also almost dies out after stomping on the clutch after WOT.
It doesnt die cause i give it a lil gas when it drops to 500 real quik.

 

Clean your IAC, it solved about 80% of my problem.

 

i had the same thing happening so i replaced the IAC valve and now my check engine light is on becuase of low throttle postion voltage imput, i need to adjust it but just dont know how.

 

The two screws on the TPS. You Screw them out, adjust the throttle body a few degrees, and then screw them back in.

Theres a tutorial on how to do it on Accufabs site.

 

what and where is my IAC? ..

 

I had that same exact problem when I replaced my stock TB with the mac 70 mm TB. It was the gasket between the TB and plenum. I had to modify it to cover the tiny mm of leak that would even trip the check engine light. It made my car idle and run like crap and almost die also. Hope you find the problem...

 

That Sounds to me like the IAC i had to replace mine and i would use carb cleaner if you do spray something in the engine

V8 to awnser ur question the IAC is your idel air control it lets air bypass when your throttle is closed it is located on the front of your throttle body and has a fat hose with what looks like a plastic box in the middle and it comes off ur intake

 

Hey shambles, You ever figure out your idle problem? How about that whistle, you ever get it to go away? Mine whistles with the accufab also. wouldnt think its a vaccum leak though, vaccum drops during acceleration.

 

shambles that description of what your car is doing is identicle to my situation im about to give up on it and take it somwhere and let them figure it out but i really hate doing that cuz i know its gonna end up beein somthing stupid...i replaced the tps..ran seafoam cleaned mass air meter..cleaned throttle body i dont know

 

HOW DO YOU ADJUST THE TPS..I DONT SEE ANY WAY TO ADJUST IT??????????

 

WHAT IS AN IAC??

 

IAC is the idle air controler located on the side of your plenum.

 

Here is the pic I used to find what the IAC is. Helped me. I had a problem starting, I would stall out when the ignition was fired. Only happened on cold starts. I took off the IAC sprayed some Carb Cleaner into it. Also sprayed some carb cleaner into the opening where the IAC was. Re-installed the IAC. Started the engine, pulled the hose off the IAC just enough where the car wouldnt stall and I could still spray carb cleaner. Sprayed more carb cleaner into the opening with the car idling. This kind of acts like seafoam, that is, it'll put out some white smoke off your exhaust, but not as bad as Seafoam. I did this about a month and a half ago. I start my car probably on average of 5 times a day, and it starts PERFECT everytime.

Thanks for those who guided me, hopefully this will guide some of you

 

The whistle is my filter, the accufab pulls more air in, so it makes my filter sing. The idle problem was fixed with a Ford PCV Valve .