My 2002 turbo Mazda Protege ES has been swapped with a 1.8L FP-DE. The car runs fine except the idle is really rough. I found some info of people that have done the same swap and it was pretty much a bolt on. I'm using the 2.0 ECU, the 2.0 injectors, 2.0 Crankshaft pulley (different RPM sensor from the 1.8), every other sensor is from the 2.0 FS.

The EGR is open due to the turbo set up.

Any suggestions to fix the idle rough? Aside from taking in for a tune.

 

i would check the cold idle control systems on the car. from the name, it would seem that they only control the idle when cold, but they also control the idle under load. from there, just make adjustments on the idle speed.

i really need some more information on how the idle is rough. does it come up and down? does it just feel rocky?

what valve cover and coil packs are you using? i am guessing that you are using the 2.0 cover with the cam position sensor in it. if not, do that. it may be where your problem lies

 

Thanks for your reply.

But, what exactly would those be?

The throttle position sensor?

The idle mostly goes down but when the car warms up it is just unstable up and down between 550rpms to 770rpms.

I'm using the 2.0 coil packs as well as the 2.0 valve cover.

Thanks again.

 

Check for any hissing noises also check the intake hose for cracks or splits. Sounds like a MAF fault incorrect air reading at the P.C.M can cause irratic uneven idle. Does the vehicle jerk at low speeds?.