I have an NA 87 Rex, and the last few days it has been bogging out in nuetral. To elaborate, when driving, whether I am stopping or merely shifting gears, the RPM drop to under 1k. At this point, the RPMs bounce back and forth between just shy of dieing and 1k several times a second . Often, it does die. If, let's say I was waiting at a light or something and the idle is doing this, I give it a little gas, the RPMs will shoot up (as to be expected), and when I let go of the gas it is almost a guaraunteed stall. It has even stalled now shifting gears on the freeway.

As a side note (whether or not this is related), when driving in second, at approximately 28MPH, the rpms will dip violently, and then recover with a fury at 29mph. Bizarre.

So far we have checked the timing (which is fine) and read all we can on trouble shooting this. As far as we can tell, it looks to be the Throttle Position Sensor which of course is a dealer only part running about $200. Before I spend money on this (which further has to be ordered) I was hoping someone else out there had experienced this problem and can either steer me in the right direction or whatever.

Any help will be greatly appreciated.

Thank you.

 

you can get a new TPS from www.mazdatrix.com for 160.

Idle should be rock steady at 750.

Does it happen at the same part of the pedal (like how hard your pushing) in all gears?

 

It happens any time I push the clutch in, or shift out of gear and am just in nuetral (clutch out.) It doesn't apear to matter what gear I am in. Yesterday, I shifted on the freeway from 4th to 5th and just in the time I had the clutch in, it wanted to stall.