[Casper98GT]

First time i found this problem i got excited and didnt buy all the parts i needed.

Ever be cruising on the highway and be in 4th and without aftermarket gears find youre self wanting get up and go, so you down shift to 3rd, depending on the MPH's... youre at about 3-4k RPM's and you throw it to the floor and it kinda feels like there are 2 giant apples in youre tail pipes?

OR...Ever be racing at the track ( Or where ever you think might be alright at the time ) and youre near the 7k redline.. and it starts to breakup real bad.

OR find your Cobra throwing that SAME GODDAMNED 02 sensor code.

Well.... The DOHC engine( and other FORD engines using dual over head cams) use IMRC.. Intake Manifold Runner Controls.. They open and close with different varables.

Problems that occur is serious carbon on whem after the 50k point mark. I didnt look into this until my ours started serious hesitation's and throwing the same friggen code i couldnt figure out until i thought about it for a day or so. They will stop opening and closing. So youre either putting in more fuel or more air, when its not needed. Alot of Cobra owners are dyno'n them and finding at the top of the graph it looks like a child started to draw with crayons.

Well, i remove the upper intake, lower, egr tubes, fuel lines, injectors... the list goes on. After removing the Lower intake you can look into the IMRC's and see that they are completely carbon'd up.

Thinking this was the problem and not looking further.. i cleaned up the IMRC's and replaced 5 gaskets. They are reusable... but not after 70k miles. lol.

So button'd it up and found still had a slight hesitation but ran MUCH smoother. Alot of people can do this and be completly happy with it after. I did another and there were actually chunks on the plates. Cleaned them up and checked the IMRC actuator after and was working properly... The guy was happy as a lil kid.

Well... mine did not actuate. The IMRC controller was INOP. Didnt open and close the valves when needed. I used a FORD WDS scan tool and checked the values of the controller and found it was not open and closing. So i get to do this all over... But good thing is this time i can use my digital so i can let everyone know whats involved in doing this.

Some people are even using Seafoam in the pcv hole. It is supposed to clean up the carbon on the ports. I had no luck with this. It cost me 6 bucks and i put it in before yanking everything off and cleaning them myself.

The gaskets you have to buy at a dealership, or get lucky online at ebay. Then i used about 6 cans of brake/carb cleaner. I also have a parts cleaner. Clean them up and work them back and fourth. Didnt use many tools, because most of the bolts are all the same. Its a day project. Took me slightly more than 2 hours to do. But will vary.

Keep a watch out for an update.......

[mdvaldosta]

sounds like a good how-to

[Casper98GT]

I have a zillion...i work on Stangs all the time. lol. Just dont have any good pics. I dont have time to snap pics when im at work trying to make money. lol. This one i have to do again next weekend. So it will be a GREAT How-To.

[JonBeast]

Nice Matt.....

You got any for us SN95's that are even slower?

[Casper98GT]

lol, yeah its called new heads, cams and pi intake ( or bullit ) Mine is REALLY slow now.... im looking into DSS long blocks right now. Its either PI 4.6, or PI 5.0

[Twist 2 Go]

Originally Posted by JonBeast Nice Matt..... You got any for us SN95's that are even slower?

no replacement for displacement

[DC97Cobra]

I need to do this to my car. I know the box works because I can feel the difference but the plates take a while to close when at a light. The car will sit there and idle around 1300+ RPM and then drop down to around 800RPM after a minute or so. I'm also getting an O2 sensor error code too.

[Casper98GT]

Sounds like you got youreself a lil project. If you have ANY questions, just PM me or email me. I will always be here to help ya!

[97snakercin]

Holy crap that really describes MY problem. I have never delved that deep into my engine but it looks like im going to. If you could post some pics or something that would help me out alot!!

Thanks

[Casper98GT]

97, i wish i did have pics. I didnt have a digital at the time i ripped into this car. But for starters.... go guy some SEAFOAM. I got a bottle at Autozone. Remove the PCV valve and SLOWLY.. trust me. SLOWLY pour it into youre pcv hose.... then let it bog and keep SLOWLY pouring it in. Its all in the directions on the bottle... and make sure you do it someplace no one can see cause people will point and laugh. Smoke will BELLOW out of youre tail pipes and it will clean that bitch right up for ya. haha. If it doesnt.... you gotta rip into the motor and clean the IMRC's.

[97snakercin]

seafoam huh? Im gonna have to try that.....
As for people seeing me and laughing?...thats ok i'll see em at the lights....

thanks for the advice man

[mustang_montana]

get a pi motor john, and then get a monster huge upper intake or blower to go with that cowl hood of yours, that would be sick. matt, are the 99+ intakes designed the same way in that aspect, or is it just the the 96-98s? just curious .

[Casper98GT]

The 96-98s have a strange intake set-up. But to answer youre question the 99 and above until they hit the S/C is much different. They dont have these problems.

[halfountain]

anyone with a 96-98 4v. needs to either get a hold of some ford racing imrc deletes or perform the deletes your self with some epoxy.. trust me it a BIG help

[scuzzdude2587]

Is this worth all the trouble of cleaning them though? From what I have read you actually gain up to 5hp (as well as never have to clean them again) from just taking them out and filling the wholes up, though you will lose some low end.

[Casper98GT]

the big difference is removing the entire thing and cleaning up. Or throwing in a can of seafoam.

[Dennis-96GT]

ok heres a question could something like this be my problem too on ma 96gt alot of times after running a while sitting at a light the fucker idles down to damn near 500 and sounds like its going to die and does sometimes of course it does have 130k miles on it and who knows if the former owner did anything to it besides change oil

[MustangMatt96GT]

Well no, because you have a 2V. What I would do is take off your IAC and take some carb cleaner and a toothbrush and scrub it and let it dry. Put it back on and see if that helps.

[Casper98GT]

yeah the cobra runs off from a DOHC motor 4v's. You have a SOHC 2v's.

Well no, because you have a 2V. What I would do is take off your IAC and take some carb cleaner and a toothbrush and scrub it and let it dry. Put it back on and see if that helps.

Make sure you clean it again after scrubbing, dont just let it dry.

[Flatline]

HELP!!!
Hey I am new to the board this thread actually attracted me especially all the helpful information I am getting from Casper.
I have a 98 Cobra and I am experiencing some of the same issues.

I got engine warning light and pulled an error code.
Advanced told me to replace the the IAC valve so I did it was kinda dirty looking with carbon inside slightly. After I replaced that I drove it down the road and engine light went off happy days. But....

About 2 weeks later (normal driving) the light came on again after a couple of hard pulls I usually don't run it any higher than 5500RPM if I'm feeling sporty, so the light cam back on and I got that dread feeling. Took it back pulled a P1516 code. They told me they thought that the IAC valve I had was defective and are ordering a new one at no cost.

At this point I think that it is something else. I went and got SeaFoam tonight and followed casper's instructions, I didn't see as much smoke as I thought there would be but I had my friend giving it steady gas as I poured about half the can into the PCV tube (did I do that right or should I just have let it bog?), when I started revving it especially when I ran it up to 6000RPM there was more smoke but then it eventually stopped, then after revving it for a couple min no more little smokes so I took off down the road, for some reason it feels like the car runs like butter now and it feels like it's not fighting as hard. I also noticed it seems the RPMs are moving a lot quicker now through the gears. I can see a difference slightly in the idle at stand still maybe about 100 less rotations per min. The car only has 46,000 original miles on it so I figured that was about the time frame casper gave I am trying to avoid the complete intake system teardown for right now.

BAD THING:
Bad thing is that even after that and it feels silky smooth now the engine light is still on! I will get the replacement IAC on Friday gonna see if it makes a difference anyone else have any ideas what might be happening let me know, this is my baby and I would like to avoid anything costly as I am trying to save for some long tubes. GET THIS MuFookken engine light out my vehicle LOL. Can someone also please try and post a picture of the cables I am looking to see move when I am checking to see if the IMRC is sticking?

*NOTE*
BnT performance has completed all the mods on my car. They also cleaned and re-oiled my K&N last time I was up there for free and I remember someone mentioning that can hamper the valves from opening at 3000RPM sometimes because the oil can gum up the works sometimes if you use too much, but that was like 2.5 months ago.

These are my mods incase this makes a difference:
BM Short Throw, 4-10 Gears, Centreforce Dual Friction Clutch, Steeda Pulleys, K&N Filter, MAC converters, Borla Exhaust, Borla H-Pipe (and yes I know I'm getting fookked b/c I have to replace the exhaust to get long tube BBK ceramics unfortunately these mods were made right before I bought it privately).