I got this one weird problem with my car. Whenever I'm on BOOST and I let go of the gas...say I'm in 4th gear, around 4500rpm and I let go of the GAS PEDAL, the car stumbles and bucks. If I'm on and off the gas quickly...it does the same thing. I can prevent this from happening, only if I release the GAS pedal slowly and then accelerate again. Any abrupt releasing of the gas pedal causes the car to stumble and choke type thing. So what could be wrong?

 

rx7's have a deceleration assist i'm not exactly sure how to adjust it or maybe u need a new one but i know its there. do some research. i'll check my chilton book i think there is something in there about it. i'll get back to u

 

Hey, just a thought here. Could be that you are not releasing turbo boost. There's a black valve that sits in a hose going from the boost side of the intake to the TID, with a vacuum line attached to it. Mazda calls this the air bypass valve, we here on the forum call it the stock blow off valve. Maybe it failed. Remove it, apply at least 11 inches of vacuum, see if it opens. Good luck!

Irv, Keith's dad

 

OH YEAH, why didn't I think of that! It might as well be that its not releasing all my boost. Cause I'm running 12psi right now and just have the STOCK BOV that's open air vented...perhaps its not releasing all the air pressure when I'm off the gas, cause its too small. I'll look into it, thanks.

 

I've noticed 4th gear @ 4500rpms and full boost, if I let go of the gas pedal the engine tends to jerk.

Also 1st and 2nd gear if you let off the cars tends to bob and jerk as well.

Mazcare said this was normal, but I do eventually want to investigate it.

 

Vaughnc, let me know what you find out, cause mine does the exact same thing like your describing!