ok .... first off it's a 96 cobra

i was getting a little hesitation in the higher rpm's when getting on it hard. well someone told me it may be the plugs. which i knew it wasn't yet i went ahead and changed them anyhow. and i felt a difference yet the hesitation still exists. mostly only in 2nd gear yet i have noticed it several times doing it in 1st 2nd and 3rd. i noticed if i roll on the gas instead of flooring it it will pass the section of rpm's it usually hesitates at and pulls quite well also at least after i have changed the plugs.. well what im getting at here is what can it be? timing a bit advanced? retarded? i also just pulled my msd dis4 off this car because it was making similar hesitations. also for this error would it show up on an OBD2 screen as an error? well just some questions to put out there. im new to the 4.6 dohc and am still learning thanks
jack

 

How many miles are on the car? You may want to yank the IMRCs and clean those out. Youd be surprised how much gunk is built up in those. Do you have any motor mods that you think can cause it? And about the MSD, those dont play very well with the 4.6s & coilpacks. The coilpacks are about the best spark you can get. Just get some 9mm Ford Racing wires and be done with those. You have a gear in it yet?

 

Usually if the IMRC's are whacked it will throw a code. Mine did on the 98-
So unless the hesitation comes in around 3,300, I wouldn't suspect those.

I know what you are talking about though. My 98 Cobra did it to me once or twice over a few years. Never happened enough to troubleshoot.

 

112K ON THE CAR. i bought the car with a CAI , msd , accel coils , msd wires , cat back , and that is it. ohh i have a 4:10 gear in the rear also.
since im new to the engine pretty much ... wtf abbreviation is IMRC? intake manifold ________?
thanks for the replies and please tell me more about the imrc's b/c i may just clean those out also. if n e one has n e free time i would like to meet some new mustang people that are good with the dohc.
thanks again
jack

 

Do a search on www.corral.net for cleaning the IMRCs (Intake Manifold Runner Control). I think there are "how-to's" and some pix to go along with it.

 

Uhm same thing hppnd to mine..........I changed the plugs and it still did it.......So i changed the plug wires and it fixed it......Mine use to hesitate around 6-7k......

 

so the best wires for my car would be what? ford racing 9mm?msd wires? i currently have the msd wires that i was told were fairly new when i bought the car

 

Id go with the Ford Racing wires.

 

thanks for the help guys.

 

Intake Manifold Runner Control. Our heads have a primary and a secondary intake port. When the car is under 3250 rpms your running off of one port. Once you past 3250 the IMRC's open and then run off of both ports. This design was created when the 4.6's came out to give them a little torque down low. You can feel it "kick in" around 3600rpms. With 112k on the car I would try to clean them first. If your plugs and wires are good then try the cleaning the IMRC's. Just do a process of elimination. But as Ryan said get rid of that MSD. But as your description it does sound like they need cleaning. Hope this helps. -Mark