Power loss at 3400 rpm's

[i8avtec]

Hey folks. I have a 97 SHO with 96k. It just recently started this problem where I get big-time power loss above 3400 rpm's. When the problem first started the engine light came on, but a day or two later the light turned off and hasn't been on since. Also, usually when you punch it and it hits 3400 the engine really starts to roar, but since this problem started no roar to be heard. Other than that the low-end and everything else seem to be completely normal. If anyone has any thoughts or ideas I'd appreciate to hear from you.

 

[SHOZ123]

pull the appearance cover off and you can see the cable end at the secondary linkage. With the car running quickly open the throttle 100% and let it snap shut. Do this a couple of times. You should see the linkage move, usually twice each time.

 

[i8avtec]

I quickly opened the throttle (the secondary is the lower one, right?) 100% and snapped it shut multiple times, and the linkage did not move as you said it would. Could that be the problem since the linkage wasn't moving?

 

[venom]

i8avtec:
I quickly opened the throttle (the secondary is the lower one, right?) 100% and snapped it shut multiple times, and the linkage did not move as you said it would. Could that be the problem since the linkage wasn't moving?

Your IMRC control box or cable has a problem. They are put together really well and are not intended to be serviced, merely replaced.

I have repaired both of ours (one was a broken cable, and the other was the takeup wheel the the cable runs on inside the box. If you don't feel like investing a couple hours investigating the workings and assembly of the box, you should be able to acquire one for about $100. Contact Ford Parts Network and see what you come up with. The box is a piece of cake to replace; taking it apart is a bit more intricate.

I find it odd that you don't have a Service Engine light on however, if anything breaks in the box (or if you repair it and don't get something just right) it should be throwing a light. Since you said the light went out on it's own, I would go someplace (autozone) and see if there are codes pending, maybe your lamp for SES just happened to burn out (does it light when you turne the key on before starting). I do know that if the box is unplugged from the harness it will not throw a light, that may be something to look at as well possibly power to the box is the issue. The codes will tell, I would start there along with checkign to see if your SES light does test when you turn the key on.

Scott

[edited] fixed typos - it was late (for me) when I posted that.

<small>[ September 09, 2003, 07:38 AM: Message edited by: venom ]</small>

 

[SHOZ123]

i8avtec:
I quickly opened the throttle (the secondary is the lower one, right?) 100% and snapped it shut multiple times, and the linkage did not move as you said it would. Could that be the problem since the linkage wasn't moving?

You are looking at the wrong cables. The Throttle has two cables attached, one is the gas pedal the other is the cruise control.

The IRM cable runs from the box under the appearance cover, turns 90 degrees and connects to the IRM butterfly linkage located behind and below the 90 bend after the throttle body. With the appearance cover off you can just see the point of attachment for the cable and the front IRM linkage actuator.

Here is a pic.

 

[i8avtec]

I finally found the linkage going by your picture and description, and re-did the procedure described in your first post, and the linkage definately did not move.

 

[venom]

i8avtec:
I finally found the linkage going by your picture and description, and re-did the procedure described in your first post, and the linkage definately did not move.

Your SES light is not on when the engine is running???? Does it light before engine start? If this cable is not moving and your SES light is not on (confirm lamp tests good before start) then you have a power or wiring problem to the IMRC control box that is under the appearance cover. Check your SES lamp and let us know.

Scott

 

[i8avtec]

The ses light came on soon after this problem started, but a couple days later it was gone when I started the car. I just now checked the ses lamp and it definately lights before start.

<small>[ September 10, 2003, 09:45 AM: Message edited by: i8avtec ]</small>

 

[SHOZ123]

Take the cover off the IRM control box. More than likely the little wheel is broken.

 

[i8avtec]

You were both right. I popped the cover off, and sure enough that little plastic wheel that is connected to the cable is broken. Now all I have to do is buy the part and I'm good to go. Thank you for all your help, you saved me a lot of time, and probably a lot of money, too. It is greatly appreciated and I'm in your debt!