New engine

[PhatAzzMarkVIII]

I told you guys that i bought a new 4.6 DOHC for my 94 Mark VIII...I have everything hooked up to spec and all the connections and everything set right. Its a new Jasper motor, and i have the problem that at idle its running rough, but then whenever the car is over 1k or 1.5K rpm's it runs beautiful. The engine has more rumble to it and its got more power. I was thinking it actually might be the Cobra motor with the bullit crank and cobra cams. Could that be why its idling rough because the computer isnt tuned for it? Or does anybody have any other suggestions on why it might be idling rough...like i said when im driving its just great but at idle its really rough.
Thanks

 

[Markviiiedrea]

sound like you could use a tune, they dint send a computer with it?

 

[ONEBADMK8]

I have a 98 Cobra engine in the TerminVIIIor and that would have nothing to do with it as too the computer wouldn't. Sounds like something vaccume wise isn't right or they didn't bolt the flywheel to the crank in the correct "balanced" spot. Could be many things.

If you used your Mark VIII flywheel then you have a Mark VIII engine because the Cobra steel crank not billet is a 8 bolt configuration whereas the Mark VIII crank is nodular iron and utilizes a 6 bolt configuration.

 

[PhatAzzMarkVIII]

No they didnt send a computer with it.. and i did use the original flywheel with it. Ive had some ppl that are familiar with this motor say that i have high rise cams in it and that the idle is an idle lope because at higher RPM's it has a major increase in power...i really dont kno but i will find out eventually.

 

[ONEBADMK8]

There stock cams, trust me. Especially from Jasper. Jasper makes KILLER engines too.