....hi guys, my 95 impreza wrx just had a full service, new plugs and i have just replaced the MAF (2nd hand

tghe mechanic has suggested it may be the "crank shaft position sensor" that needs replacing, but as no-one around here has a diagnostic machine i dont no for sure.

 

I would not buy a CPS sensor without properly checking it.
When they go faulty they normally break down so the car wont start or cuts out compleatly when hot.

Is it missfire or running rich/lean more info on actual running fault would help.

Jase

 

Not sure on your model if speedo runs off speed sensor, but sounds like you have wiring problem or sensor gone down. Check your batt connections and earth strap on engine to start with.

If it runs better when cold, probley running to rich. This could bo down to bad earth on engine, poor joints on wiring connectors or Maf fault, TPS fault Coolant temp sensor fault, to name a few. I still think CPS is unlikely but without actually testing cant say.

Just a thought all your air pipes are on correctly and not blocked, and vacume pipes and not split, any of these will cause bad running due to ECU "seeing" wrong air pressure, vac readings.

 

cheers for your suggestions mate

 

gonna take it to another garage mon to check it out as y/day it was running sweet as?!?!?!

 

cheers

 

If it's a '95, the speedo runs of a cable from the gearbox. If it's jumping up and down that could be a problem with the cable, or the convertor (if you have one fitted) that changes it from km/h to mph.
I don't know if the ECU needs speed information from the speedo to alter timing and mixture, etc.?
Are all the coil packs in good nick? Has the air been damp when it's been running rough?

 

yes it is

 

just had a call from the garage earlier - apparantly the coil packs are f**ked!! cracked and split everywhere - getting replacements fitted tomorrow!!

should this cure the whole problem?

cheers4 all yer help guys!

 

the coil packs ive pu in are used but look fine