Seems my car likes to hesitate or buck at high rpms. It feels exactly like the spark plugs and/or wires are bad, but everything is new. Im thinking bad TPS. Its adjusted correctly but still may be bad. Whats the limit for resistence on the TPS? Does anyone have any other ideas? Also it does not do it all the time and I do not have to be under hard boost or acceleration.

87t2

 

Fuel filter/pump good?

 

Ya Ive done every tune up to this car and I've regrounded the ecu and other things. I'm telling you I combed everything. Does this sounds like a bad tps?

 

It seems to happen at about 5200 rpms. BTW I have my safc set kind of rich cause I have to get it tuned. I also have a walbro high pressure pump rewired with rb full exhaust and stock intake. 145k miles

 

Did you ever try replacing all the vaccum lines? If so perhaps you didn't put the "pill" back into the boost sensor vac line. That was my problem.

 

I've done extensive tuning up on this car. If you can think of it, it has most likely been done. Basically this thread is asking if a bad TPS can be tested, and will a bad TPS cause a bucking at high rpms.

Yes the pill has been replaced with a new one from Mazda

 

In my research of a similar problem, I found you can test TPS w/ multimeter. Two different paces 2 times each.. once closed, once full throttle. Don't have #'s but I got em from a PDF manual on http://www.iluvmyrx7.com

Do you know if anything else can make TPS go out? Or if they just die now and then ?

 

u might be running too rich and also check out your ignition timing

 

Its not the TPS. The 87 TPS is not a full range TPS and the signal is ignored at anything over 10-15% throttle. I had this exact same problem with my 86 NA. Turns out it was the AFM flapper door vibrating at high RPMs. I swapped the AFM and the hesitation went away.

 

what is the afm flapper door

 

OK I will check it all out tomarrow when its not raining... Hmm... it didnt do it in hot weather...

 

You can pull off the TPS plug and check the plunger for resistance.

 

FCD?


-Ted

 

My 87 does the same thing ... I never noticed it till 2 days ago. I never really run that car hard.. but I took it out for a good "blow out" run just before my smog test. But it did not do it at WOT, just if i tried to hold it steady at say 5.5k

FCD at 5k ish rpm's? you tell me .. your the guru is that plausable?

 

Like Ted said, do you have an FCD? It sounds like fuel cut. Need more info. What boost are you reaching? Does this happen in all gears? Have you checked for error codes? How rich is that S-AFC set too?

 

The 86-8 TPS IS a full range...it is at 1kohm at idle, and 4-6kohm at WOT. Test it out yourself. Another ay I know it is BS...it caused the EXACT same problem on my car. For a while I couldnt even rev over 5500rpm...i unplugged the TPS and driveability got a LOT better all through the range. Any s4 t2 owner will know what Im talking about with the little "switch sensation* right off light throttle when trying to cruise at low rpms...the throttle acts, no matter how you ease in and out of it, as an on/off switch. Mine had bad hesitations at high rpm, now it doesnt, plus the low rpm "switch senation" is gone. Try it out...just reach under there and unplug it and go for a drive. Mine has been unplugged for 2 months with no ill efffects, and I talked with others who have run w/o one for over 2 years.