Drove my car today to make sure that the hesitation was still gone since the new plugs and other new parts and to test my Mazdatrix short throw shifter out. Drove it down the road after it warmed up and no studder until 4800rpms in 3rd gear, none in first or second. Then at 6000rpm the car acted like it ran out of fuel until the rpms came down around 2500. Then the car drove fine all the way home except the 4800 rpm studder is there still. Got home and had it out side the garage and tried to rev it and it wont rev past 1500 rpm if you more than breath on the gas pedal. If you ease it in extremely gently you can get it to about 5500rpm but then it acts like a launch system/rev limiter.

Anyone have any ideas of what is wrong? or what to test/check?

The car has new:
Sending unit
Fuel Pump
NGK Platinum Plugs
Mazdatrix Plug Wires
Oil and Filter

Checked all connectors to injectors and fuel pump and all engine bay plug connections and problem is still there. The grounds were all sanded down and polished up recently too.


Next thing is getting all the injectors cleaned and flowed.

 

check the injectors and fuel filter.. www.witchhunter.com is a great source for injector testing and cleaning of the injectors.

 

omp limp mode.



You need to pull the cel codes and confirm.

If you keep driving it, the OMP can take out the ECU. Ask me how I know

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/s5-mop-ecu-failure-diagnosis-710938/

 

do S4 cars have omp limp mode? I was told they didnt. If i dont work this ous soon its going to be headed to KD rotary

 

your afm connector is Loose.

 

Mmmmy bad, I thought you had an 89.

 

my guess AFM or TPS

 

checked the AFM connector and its not that. Should i replace the TPS and where should i get one.

 

i would test the tps before replacing it. have you tested the afm per the fsm?

 

Just DISCONNECT the TPS and rev it. If the plunger in the TPS sticks, it'll cause fuel cut. Sometime this will remedy itself by unsticking.

I'm talking about how you can't rev over 1500rpm sitting the driveway, not the rest of the problems. IF you disconnect the TPS and now you have full revs, then shut the car down. Then get under the hood and open the throttle all the way and reach under there and move the piston on the TPS back and forth. If you feel no resistance when you push it in by finger, then the internals/spring is stuck. Flip it several times and it MIGHT free up.

I assume everbody knows how one of the functions of the TPS is to cut fuel at a given time, and how knowing that explains why the car wouldn't rev over 1500rpm in the driveway.

 

It was the TPS. So i took it off and then sprayed WD-40 down into it and moved the plunger back and forth for about 3 minutes and kept spraying it. Then took the air compressor and a blow gun and blew all the WD out of it. Low and behold it works like brand new again. It even fixed my higher RPM problems. Thanks for all your help!!!