revs only to 1500
 

So the issues is on a 1990 vert i just bought that i believe is stock with 150k. Sometimes when i start it up and give it any gas it will only rev to 1500 and then goes right back down to idle and then back up over and over and over again. Its like the car is in limp mode but i dont have any lights or anything lit up in the custer. Yes the CEL/MIL light comes on with the key so its not like someone removed the bulb. It only seems to happen at startup however i did leave it idle for about 10 minutes today and it pulled his trick on me.

i am sure its something simple but my turbo hasnt had any problems and i work on vw's for a living so sometimes this mazda thing doesnt click. So where should i start looking?

Ben

seriously i need a point in the right direction here. It seems to do it more warmed up since i have never had to happen cold, and happens more when doing lots of stop and go kinda errands. Just did it to me trying to leave my house after work. Really getting old as its happening more often.

so throw something out there

Could be a vac leak or maybe wrong timing.

You check the MAF?

sounds like a bad OMP, it won't toss on a CEL immediately but it should be leaving a code if you look for it.

OMP = 10-20 minutes to driving and suddenly the motor goes into limp mode. I agree with Karack that you should get the OMP replaced. The ECU codes are easily retrieved and if you get any OMP related code....be prepared to spend some serious money to replace it.

used parts are your friend.

mazda has some steel cajones for putting a $1.6k price tag on that little ball of shit.

gotcha i was assuming that this was going to be the problem but figured it would throw a code (i work on newer vw's and if you hit the windshield wiper switch wrong i swear to god it throws a code)

I will double check the vaf and omp. but first i will try the jumper code puller and see what happens

I don't understand the exact problem. At one point it seems you start the car and try to drive it but the rpms won't go over 1500 rpms at all and the revs then go down then back to 1500 rpms again and again. Like you'd never be able to even get out of the driveway like that.

IF that is the case..................unplug the TPS connector and see if you can drive it. I KNOW you'll run into limp mode later but that'll be somewhere over 3500 rpm (guess) NOT what you seem to describe.

I'm saying if disconnecting the TPS now lets you drive the car with none of the 1500rpm stuff anymore............I'd suspect the TPS and have NOT A CLUE why you don't get a code/warning light.