gerdman

Wanted to say hello and ask some of you experts for some advice. Have a 05 stang 4.6 that does not want to run right for me. I did do extensive google and forum searches but nothing with the same kind of issue that I seen. Problem is it has a warm idle of about 1300 RPM which is way to high for me. Second issue is what really gets me. If I rev in neutral to about 2k, the rpm will hang for about 3 seconds then slowly drop to idle. If I rev past 3k in neutral the rpm will drop to 2000 to 2500 rpm and stay permanently. Now if while its hanging at the 2500 rpm point and I press and release the clutch it will drop back to idle of 1300. Does the same thing while driving. What I have done so far is remove the TB and clean with CRC cleaner gently. Did the same with MAF and its CRC cleaner. While doing this I had the battery unhooked to do the idle relearn procedure. This did not fix the issue and want advice before I get poor at a dealer. NOTE...everything visually appears stock but it runs like it has cams in it. I assume by the sound FRPP cams but do not know for sure as car was purchased this way. Has Flowmaster mufflers and stock cats. Thanks in advance.

BigChuck74

Is the care throwing any trouble codes?

gerdman

Ok so today after work I installed a new stock throttle body from ford racing. Exactly the same as old one and no change. Cleaned the MAF again and inspected the wires, all good. I checked and the car does still have the metal arms and such so I guess the IMRC is still there. Checked the manifolds and the look stock. Everything about the engine looks stock. Sounds like it may have mild cams still, just like the FRPP but higher idle. Would have to pull the cover to confirm hopefully if it has part numbers visible. Still no CEL and even checked for vacuum leaks again and found nothing.

PullTab

Do you have a CAI installed? Do you have a tuner? If you run a CAI without a tune for it, the car will run like the way you are describing. It sounds like a MAF , throttle position sensor, or tune problem to me. Did the new throttle body come with a throttle position sensor, or did you swap it?

shinerttu

Did replacing the TB help? When I heard of your symptoms it reminded me when I cleaned the tb on my Nissan, I didn't know what I was doing and I sprayed everything including the electrical components. My car acted like yours for like a month after that... So I'm hoping when you replaced your TB you are all good? What makes you think you have cams? It would help of maybe you posted a sound/video clip

gerdman

Yes the replacement TB was a fully dressed stock replacement from ford racing, TPS and all. I do not have a tuner for the car as it is new to me. Everything on the outside of the motor appears stock....even the air intake. Reason for cam thought is because of the way it idles. Sounds just like hot rod cam but at a higher idle. Does that little chuga chuga lope as it idles kinda like those cams do. Either that its just running like total doodoo. Drives fine though as long as you don't stop or idle.

shinerttu

I know you cleaned the mad but if you know another mustang owner or can test a new maf I would try that next. Sorry I can't be of much more help. Doesn't make sense to me that it runs fine just doesn't idle or stop well.

Bueller99

Previous owner possibly put a custom tune on it. They can write a tune that simulates a cam. Possibly returning to stock tune is all that is required. Unfortunately if you didn't receive the tuner with the car you wont have the stock file.