Some Help....Please!

[MR98Cobra]

This is strange, and somewhat hard to describe. I just started having this problem...when I shift into fourth gear the car falls flat on it's face. It almost feels like I shifted from third to fifth. It just boggs down, then picks up again like everything is normal. It's very inconsistant and only happens once or twice during an hour's drive. Any feedback would be appreciated.
Anyone had this type of problem before? I've tried a few searches, but nothing yet.

Thanks!

 

[99 ATI Cobra]

I have had strange problems like that, to which no one has been able to give a good answer. Mine surges or stumbles in 2nd and 3rd gear only under mild acceleration. The most common reply is to go get a tune. I'm like you I would just like to know what could cause such a problem so I can fix it. Not just go spend $100.00 or more for a tune to patch it up until it gets worse or breaks down. Maybe you will get lucky and this be a more common problem than mine with a good fix.

 

[MR98Cobra]

99 ATI Cobra:

Thanks a lot for posting a reply, I really appreciate it.
Believe it or not, it actually helped. I've got 46K on my car, and maybe it's time for some new plugs wires, etc. I'll give it a shot, can't hurt.

Thanks
Mark

 

[99 ATI Cobra]

You may need to clean the MAF and AIT sensors with some contact cleaner also. Fuel filter was my first maintenance item, and a pain to change on the IRS cobra's.

 

[sinisterblack98]

Not sure on the problem, but you definately NEED to change the plugs w/ 46,000 miles on it! On two '98s, 2V and 4V, I changed them with 12-15k and it woke the car back up (actually brought the tire chirp back!). The factory plugs are actually two different types on opposite sides of the engine (replaced with one type stock replacement per factory).

Go right up to the max. gap (.056") and check 'em every 5-6k. I don't leave a plug in for longer than 10-12k on any fun car.

 

[MR98Cobra]

What plugs and wires do you recommend?

 

[djtech]

I don't have any experience w/ your model Cobra but I've read a lot of threads that described your problem. Is your service engine light on? Your symptoms sound like stuck IMRC's.

This is strange, and somewhat hard to describe. I just started having this problem...when I shift into fourth gear the car falls flat on it's face. It almost feels like I shifted from third to fifth. It just boggs down, then picks up again like everything is normal. It's very inconsistant and only happens once or twice during an hour's drive. Any feedback would be appreciated.
Anyone had this type of problem before? I've tried a few searches, but nothing yet.

Thanks!

 

[99 ATI Cobra]

I've been told if you plan to install a power adder, don't use the platinum plugs. Use the cheap ones and change them every 15,000 miles or so. Regular Autolite resistor plugs are good and NGK is all I ever run on my race motors.

 

[MR98Cobra]

djtech,

My check engine light is not on. I have no issues anywhere but fourth gear, and that is inconsistent. I recently pulled the IAC and cleaned it, and since I did that I have not experienced the problem again. I'm not saying it was the IAC, nor am I convinced that it was the IAC, but no hiccups since...very strange. My plugs haven't been changed, so I'm going to change the plugs and put on new wires. I don't think it's the IMRC's because I've read a lot of posts regarding issues with them, and I've never experienced the lag that people complain about. The car runs great, still pulls hard, and gives no signs of any issues, starts right up, idles fine. I appreciate your advice, it helps. I read the procedures on cleaning the IMRC's in anticipation that I might have to perform it. Is there any way to tell if the owner before me deleted them. The car had all the bolt-ons already installed when I bought it, so the IMRC could be gone.

 

[djtech]

That's true you should feel this at lower RPM's in any gear. That's the only thing I could think of besides the computer doing something. Perhaps a custom dyno tune is in your future.

djtech,

My check engine light is not on. I have no issues anywhere but fourth gear, and that is inconsistent. I recently pulled the IAC and cleaned it, and since I did that I have not experienced the problem again. I'm not saying it was the IAC, nor am I convinced that it was the IAC, but no hiccups since...very strange. My plugs haven't been changed, so I'm going to change the plugs and put on new wires. I don't think it's the IMRC's because I've read a lot of posts regarding issues with them, and I've never experienced the lag that people complain about. The car runs great, still pulls hard, and gives no signs of any issues, starts right up, idles fine. I appreciate your advice, it helps. I read the procedures on cleaning the IMRC's in anticipation that I might have to perform it. Is there any way to tell if the owner before me deleted them. The car had all the bolt-ons already installed when I bought it, so the IMRC could be gone.