stumble under load
 

Hi all - wondering if you experienced people have had this problem( I did try to search this)- I have an intermittent stumble/misfire under load - sometimes it runs perfectly- other times undriveable as it will not accelerate. My mechanic ( an experienced RX7 shop) has checked engine ground and fuel filter, EGR valve and I just decided to replace the fuel pump as it is likely original. This car has about 140k kms and about 30k kms on the factory rebuilt 13b and installed by Mazda. The car idles well under all circumstances and performs great when it works!! Any ideas? Thanks Paul

No ideas out there? No help with new fuel pump and injector clean- going to check on TPS and other related items.

Does it stumble at the same rpm level or not. You could try unplugging the TPS and see it behaves the same.

Thanks Satch- it does not have any relation to RPM just won't accelerate. Mech has a spare MAF and will try that tomorrow- he also suspects the TPS -I will let all know when resolved-thanks Paul

try changing the main fuel filter on the car as it has most likely never been changed.
It's under the car,pretty well under your left foot when you sit in the driver's seat..on the frame rail.
By the way,the injector clean is not an effective "tool" with these cars...BUT getting the Injectors CLEANED( as in serviced) is.

Thanks for your input misterstyx69 - my mech has likely found the culprit- a bad ( intermittent) connection on the cable to the TPS - got my fingers crossed! Thanks Paul

stumble under load
 

Good info. I just picked up a '93 with an extreme stumble under any gas pedal over 1/4. Probably why the previous owner sold it eh? I don't have the car delivered yet, but when I get it, I'll check the TPS connections and pull the codes for sure.

Has it been fixed? Was that the problem? just curious.

fixed
 

The fix seems to have been that bad connection to the TPS- although it ususally acted up in warmer weather and it has been cool here since I got it back but so far so good! Thanks Paul