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adjust theTPS

 

You may have more than one problem. Bucking on deceleration, particularly in low gear, is a common problem with RX7's. Search on bucking and you'll see what I mean. Yes, first make sure the TPS is functioning and correctly adjusted. Then make sure the idle speed is correctly set. Then, look for and fix any vacuum leaks. Finally, check the major grounds in the electrical system.

 

There's also the spring plunger ( can't remember the proper term) on the back of the tb. When you let off the gas it keeps the throttle plates from shutting too quickly. Had mine off and my car bucked. Not violently though. Like chuck said it's probably more than one problem.

 

The dashpot?

 

Yes brent was talking about the dashpot, and that along with the tps is what i would check first. I would also check for anything loose under the car or a worn u joint in the driveshaft

 

It's a round piece with a threaded rod that's thread through the bracket on the top passenger side at the back of the throttle body. Just in front of where you're throttle cable connects.

 

hmm.. ive been having this problem as well. im pretty sure my tps is working correctly and id be damned if the clunking wasnt coming from under my feet. i was thinking it might be the pressure plate? but i guess ill check the U joint now as well..

 

My car did this as well, I changed the plugs and the fuel filter. Problem went away.

 

I have slight bucking in 1st and 2nd when at low rpms on decel. Pretty sure TPS is set right but I should check it anyway. Never touched the dashpot before. Pretty much everything on my car has been replaced already. Sometimes my rpms drop to around 500 when I push in the clutch coming to a stop and then steady out to 750 idle. I'm thinking it's might be the tps.

 

I'm not sure but I think on light pedal and decelaration a bad o2 sensor could cause this as well.

 

i noticed a substantial lessenning of bucking during decel with new engine and tranny mounts installed over worn and broken/sheared off ones.

 

OEM, solid or mazdacomp? I was looking into getting some mazdacomp ones since I hear solid mounts cause too much vibration in the engine and also cause more stuff to break in the drivetrain on hard launches. My mounts still look in decent shape.