Rpms Sticking Something Vicious

[BigMikeT]

This happens every single time without failure. The run fine and normal until I hit 35 then when I press the clutch to shift my rpms shoot 2-3.5k on rare occasions almost 5 and it will do it until I let off the clutch. But when I do the car slowly accelerates. It will do this until I slow back down to 30. I've checked to cable for hangups I've checked the pedal, I've checked the TB to see if was stuck open. Nothing. The thing that makes it hard for me is it only does it above the 35. I'm stumped.

 

[Bullitt347]

Unplug the IAC (idle air control) valve and see if it still does it.

 

[BigMikeT]

Already did that, I have a cold air intake but it's been on there for years but for giggles I put the old OE intake on it, still does it. I'll be working on this all day today so shoot me anymore suggestions and I'll do em as I get there.

 

[wmburns]

+1 on performing a basic IAC functional test.

Does your speedometer work? Is it accurate?

Are there any DTC codes?

Does the motor make good power otherwise? Does the motor use oil? Coolant? How's the gas mileage?

When was the last time the PVC valve was replaced(really. That long ago. Then it's time for some maintenance)?

Are there any vacuum leaks? Are there any Exhaust leaks?

FWIIW, the odds favor a vacuum leak or a bad PVC valve. If the IAC valve were bad, likely there would be problems with the slow idle.

Here's more information on how to trouble shoot IAC/idle issues.

http://www.allfordmustangs.com/foru...-dieing-idle-idling-rough-14.html#post2260649

 

[BigMikeT]

Yea just checked all the vacuum line, everything checks out with a visual inspection, that is till I got to that pcv, it's was stuck open. Slammed it my hand and knocked it loose but it's shot. I pray that could be my problem. I'm open to any other suggestions it will be a few hours till I can go grab a new one.

 

[BigMikeT]

New pcv valve and problem solved, thanks guys