shftin2gear

I have a problem with my stock '83. When in gear, it decelerates very rough under about 2500 RPMs. It will just start bucking back and forth unless I put the clutch in. I'm stumped, the engine runs pretty smooth other than this...

mazdaverx713b

iTrader: (91)

sounds like the coasting valve is not functioning properly.

shftin2gear

Is that the same thing as the shutter valve? Because I recently replaced it.

j9fd3s

iTrader: (3)

yes. you may want to check the throttle position sensor (yes it has one!), it controls the timing advance solenoids, and this is active on decel. maybe next on the list would be the anti after burn valves in the ACV

shftin2gear

Okay thanks for the help. Now, how do I check the TPS?

flight_of_pain

Check all of the motor/tranny mounts, rear end bushings, and u-joints. Drivetrain lash seems to be one of the more common complaints that used RX7s i pick up have.

Isaac

kencunm

iTrader: (3)

I agree with flight! Get under it and check the drivetrain/driveshaft for looseness. I'd guess that to be the weak link.