98 Cobra Problems

[modster530]

Hello Everyone! I've got a problem with my 98 Cobra and was wondering if anybody could help.

My Cobra has a Vortech 8lbs. S-Trim, 36lbs. injectors, 255lph intank fuel pump, PRO-M 80mm mass air meter and other mods that I don't think are relative to my problem.

Now the problem...the car starts up fine and idles down to normal idle speed. I'll drive the car around for about ten minutes and then I'll notice a huge drop in power (if I let off the gas, the engine will cut off). So, I'll pull over and restart the car. The car will start up fine and drive forever without the engine cutting off unless I turn the engine off and let the car cool down for a long period of time. I will also feel violent hesititions (kind of like I was learning to drive a stick for the first time) on and off during my drive.

I used a friends Snap-On scanner and pulled the following code:

P1516 IMRC Input Error Bank 1

I thought that the 98 Cobras had the IMRC removed from factory but after reading a few postings here I have found that they weren't but replaced with a set of plastic IMRCs.

Any help would be greatly appreciated...Ed :shrug:

 

[svtcobra553]

I had a simular problemwith my runner controls I forget
the exact code it was but the car would be a dog in the upper
rpm's it ended up being the plug to the IMRC control box had come loose. the problem was intermitant and only tripped the check engine light once. If it's onlyone side thats not opening like the code makes it sound like then mabye one of the cables that open the butterflies snaped. hope this helps. O and the runner controls are all metal from what i've seen.

 

[Booyah]

Exactly what svtcobra suggested, sounds like a runner cable snapped. Not a common problem but have seen it before.

 

[modster530]

Thanks guys for the input. I'll check on that plug.

I did some reading in regards to the IMRC system and noticed that the secondary plates do not open until 3250 RPMs. So, with that in mind I drove my car around when it was cold without exceeding 3250 RPMs and found that the car ran fine and didn't surge. I then brought it up over 3250 RPMs and the car still ran fine but my problems only occur when the engine is cold.

It's hard to see the cables from the top...any idea on how to check the cables without taking the intake apart?

Hmmm... :idea: ...would replacing the IMRC system with the delete kit solve my problems or would it just add to it? Does anyone out there have any problems at lower RPMs with the delete kit?

Thanks again...Ed:beer:

 

[GR8WHITE]

An IMRC delete won't hurt your cars low RPM performance with the SC. It would be a good mod for your car. It should however be allowed to warm up before driving. Even in my stock 96 Cobra, if I cranked it up and tool off cold it would hiccup when the secondaries opened up. Once it was warm it was fine. It was even worse on my 97 Cobra that was SC'd. All that extra rush of air entering the motor before it is up to operating temperature just adds to the hiccup.

 

[modster530]

How much I am looking at for a set of IMRC delete plates? Will I need to purchase new gaskets or are the old gaskets reusable? Is this a hard mod to perform myself? Also, what happens to the IMRC module/actuator and won't this mod trip the MIL? Sorry about all the questions. Thanks again!

 

[Boosted32V]

Modster, if you want to put in the FRPP(SVO) IMRC delete kit then you will have to have your chip re-burned to shut the IMRC off. If not then you will have to plug in the IMRC control box so that your programming stays the same and not trip the MIL light. The 96 to 97 Cobra's had the Aluminum IMRC's on thyem and the 98's had the plastic IMRC's that were also port matched from the factory like the SVO IMRC's. It is pretty simple to install and you will have to use new gaskets if they do not come with the kit.