I'm having idle issues with my 408. The idle hangs at about 1200 until I make a complete stop then it will drop down to about 950, also when I rev the engine it hangs at 2000 for a few seconds then drops down to 950. When driving around town if I jump out of the throttle it wont find idle and dies. I had a vacuum leak between the throttle body and intake and took care of that I also had a small exhaust leak by the back oxygen sensor and took care of that. I tried to adjust the throttle body cracker, but if I turn it enough to get rid of the hanging idle then it wont start up and stay running and also dies alot at stops. My maf is the original stock one and is in kind of bad shape could it cause a problem like this?

 

No advice? Well I went ahead and ordered a new maf. I also plan on checking/cleaning the iac tonight.

 

Sounds like your tune is jacked and needs to be fixed.

 

It was tuned by speed inc. so I'm hoping that's not the case.

 

that sounds like a tune issue.... my cam did that to me untuned, but worse.

 

Carb swap baby, its what I did

 

I'm not positve but I would go out on a limb to say his is fuel injected.

 

Well I cleaned the iac and disconected the battery to reset fuel trims took it for a drive and it wasn't dying on me anymore. The idle is still hanging a little bit and when I rev it in neutral the rpm's come down and hang at about 2000 rpm's for a couple seconds before dropping down to idle at about 950. It's frustrating to get my car back and still have to trouble shoot it myself. I've went through everything I can think of and now it seems like the tuning has to be off.

 

retune

 

Check to make sure you dont have any vacume leaks. How are the brakes? Just by what your saying I would check the little stuff first. Leaks will cause a funky idle with or without mods.

 

The brakes are fine. I started with vacuum leaks and did find one between the throttle body and intake that helped a little but didn't solve the problem. I'll need to buy some starting fluid and check it over again.