1997 cobra missfire's at 3250 rpm

[newtoy]

I am having trouble at around 3250 rpm's the car is stalling? missfireing? and backfireing. I have had this problem for about a year now. It comes and goes. At first my local stang guru thougth it was the pro-m massair flow and 36 lb injectors. changed these out six months ago went back to stock and the car ran ok for a while then acted up for a couple of days. Any it's do'in it agian and im starting to get really pissed!!!!!! any ideas

 

[mystical]

That is when the imrc are suppose to open.

 

[Teksid281]

Sounds like an IMRC issue, like maybe they are not opening. Rev the engine via the throttle linkage on the tb from under the hood, watch the 2 black cables that run down behind the engine between the intake and firewall. Rev it high enough and they should jump rather sharply.

 

[Wynn]

And have fun cleaning them, if you have to. I just got done doing it, and it was a pita. Not too hard, but time consuming! Took me about 5 or 6 hours total.

 

[blackfang]

Sounds like an issue with the IMRC's.

Here you go.
http://www.svtmustangcobraclub.com/media/pdfs/tech/IMRC_Cleaning.pdf

 

[Toasty]

I am having trouble at around 3250 rpm's the car is stalling? missfireing? and backfireing. I have had this problem for about a year now. It comes and goes. At first my local stang guru thougth it was the pro-m massair flow and 36 lb injectors. changed these out six months ago went back to stock and the car ran ok for a while then acted up for a couple of days. Any it's do'in it agian and im starting to get really pissed!!!!!! any ideas

Clean your IMRC's. Are you running an aftermarket gear ratio in the rear? If so, you can probably just do IMRC deletes.

 

[newtoy]

1997 cobra

hey guys i have already done the checks at the back of the engine. took the car over to my town local stang guru and he hooked up a snapon computer to the car. it came back with the imrc stuck closed? Anyway i also am losing fuel pressure at this same 3250 rpm range. changed the filter . blocked of the pressure reg. still same problem. this car has a vortec (t-rex) (50/70)fuel pump. Also i do have 4:30 gears ,1to 1 comp , underdrive pulleys. off road h pipe, 62 mm intake butterflies . Right now i have stock injectors and maf but have a pro-m maf and 36lb injectors

 

[SNAKEYE]

Get rid of the T-Rex and install an in-tank 255 lph Walbro.