help!!!! 96 cobra wont idle!

[Prostyle]

Hey guys have been huge problems with the car idling.

Car will turn on then die unless I keep my foot in the gas. I replaced the iac today with a new one and also checked the tps and everything is fine.

When I start the car and keep the rpm's under 2k my wideband is reading 21.8. Car drives fine underload and under boost. It has a slight surge if im under 2k rpms.if I put the car in netural the car just dies.

I had some massive preturbo exhaust leaks and those r fixed now and car idles bad. Would fixing those cause the car to idle bad and need retuned? Or maybe im over looking something?

Any ideas guys?

 

[03bluemach]

man i would start by (and this is just me ) cleaning the MAF and un hooking the battery let it reset ...

 

[Prostyle]

unhooked the battery for 20 minutes and cleaned the maf didn't help one bit lol. I checked all the vacuum lines and they all seem to be hooked up and not leaking. Would a stuck egr or anything to do with the egr cause this sort of problem?

 

[96snake719]

Im having the same problems with mine, only its fine until you beat on it a little after that it barely wants to idle, then let it sit for a little while its fine again? Could a vaccum leak cause this? OP I cant find any leaks either but when I was having my high idle issue my tuner said the IAC was trying to compensate for a vaccum leak, so Im thinking theres gotta be one somwhere and causing all our problems.

 

[Prostyle]

That's how my problem started. Use to be when the car was cold it would idle fine. Beat on the car abit and it was acting up. Took the car to the track make a few passes and wont idle at all now. Im replacing the upper intake gasket here soon and maybe there is a leak. If it doesn't help I will be taking the car to have it smoke tested and fine any leaks the car has.I just can't figure it out and its really killing me.

If any one else has ideas feel free to throw them out

 

[Myzticsnake]

Buy a cheap vacuum gauge and see what sort of pressure you are pulling.

Disconnect your maf and see if the car will idle that way.

Also, having it running crappy and then taking it down the track doesnt sound like the best idea to me for the future.

 

[Prostyle]

I will try unhooking the maf tomorrow. Pulled the upper intake and the gasket seems fine. Vacuum hoses look good. No idea on what's up with the idle.


The car drives fine and is perfect in load so I took it to the track lol.

 

[Prostyle]

Pulled the upper intake and replaced the gasket didn't help one bit. I unhooked the maf and it did the same thing but the car seemed like it was actually trying to fight to make it idle with the maf unhooked.



when the car starts it revs up a bit and shows 20vac but then idle drops and the vac drops to about 10 and the car dies. Sideband is showing 21 throughout but it seems rich from the exhaust not lean.


Any suggestions guys? Im willing to try anything at this time to get it to idle right again

 

[encasedmetal]

Pulled the upper intake and replaced the gasket didn't help one bit. I unhooked the maf and it did the same thing but the car seemed like it was actually trying to fight to make it idle with the maf unhooked.



when the car starts it revs up a bit and shows 20vac but then idle drops and the vac drops to about 10 and the car dies. Sideband is showing 21 throughout but it seems rich from the exhaust not lean.


Any suggestions guys? Im willing to try anything at this time to get it to idle right again

check list:
fuel filter clean?
fuel pump working?
fuel pressure reading?
smoke test?
maf clocking?
tune

 

[b00stin]

Check the egr valve ... make sure it isn't stuck open...that will definitely cause a shitty idle

 

[Prostyle]

Going to clean and check the egr after work tonight. Also going to change the fuel filter and check fuel pressure. I know the pumps r working as I can hear them as im running Bosch 044's inline

 

[xtremeskime21]

is your tb blade sticking?

 

[Prostyle]

Im having the same problems with mine, only its fine until you beat on it a little after that it barely wants to idle, then let it sit for a little while its fine again? Could a vaccum leak cause this? OP I cant find any leaks either but when I was having my high idle issue my tuner said the IAC was trying to compensate for a vaccum leak, so Im thinking theres gotta be one somwhere and causing all our problems.

My car did this exact thing man. It will idle high then drop down and die sometimes. I could let the car cool down and it would run fine till I drove around more. Ill let u know soon as mine is fixed. Im making a video tonight of what its doing and replacing all my vacuum hoses too

 

[96snake719]

ok awsome, its really annoying as you know lol

 

[Prostyle]

Well guys still no luck!

Checked fuel pressure.its at 40without vacuum and w/e it should be with vacuum

Changed fuel filter.

Pulled egr and cleaned it and checked it. Its good

Replaced all the hoses going into my upper intake.

Since im running a pmas hpx can I try a stock maf from a newer mustang ?

Also the car drives fine under wot and load past 2krpm. Think it could be a bad coil?

 

[Prostyle]

Double post!!!!

Any one wanna buy a cobra? That's about how I feel right now

 

[Hockeyman48]

Have you checked your TPS voltage at idle and full range also?
Never mind saw it was checked already!!

 

[encasedmetal]

I have a feeling that your Maf is your issue- what does your tuner say about it?

 

[03vnmous_snk]

ya had the same exact problem with my s/c 97 cobra turned out to b my intake gasket now it runs mint

 

[Prostyle]

My tuner thinks it might be the tune but then again he wants 250$ for a retune so im trying all my options first.

Yeah I replaced the intake gasket with a new one and also used rtv on it to make sure it sealed good. With the maf unhooked the car will actually idle somewhat but still dies.

I have a video on my phone that I will upload soon as I get home from work.

If the maf was bad would the car run fine under load? I wouldn't think it so but I might be wrong that's why I think its something else.

Would a stock maf from a 06 mustang work to test to see if mine is bad? Friend said I can borrow it and see if I can get the car to idle with his