To cut a long story short my car has had serious problems half way through it's first long motorway session for a while. It's recently had new NGK PFR7's but don't know if this is related to the problem.

I had been driving for about 1.5 hours when the car suddenly started stuttering and hesitating, the rpm meter dropping 500rpm each time. Trying to go faster resulted in back firing. Lookign back on it I do remember a couple of split second hesitations earlier in the drive.

Now the car will start and when it's cold it seems ok but when it gets hot it just misfires etc. The rpm drops to zero sometimes, and flicks back up. It even stalls completely on occasion and is difficult to start.

When it's hot I can crawl at 30mph, by hardly depressing the loud pedal but even then I get a bit of hesitation and the car just loses all power on occasion the rpm meter dropping to zero.

If I sit with the engine revving it revs nicely at a steady 700rpm like it should, but I did notice, straight after coming of the gas and depressing the clutch that the revs seemed unstable for few seconds, going up to 1500 and down to 1000 then back up a little without any input from my foot on the accelerator.

I changed the coils today (did not check the new plugs) and it seemed fine at first (cos cold) but as soon as it got hot, same problem.

Any ideas please....

Oh, it's a MY94WRX wagon. And all of this happens without any boost, I don't think it's turbo related at all.

Cheers

 

Hi m8, it sounds like your maf sensor has packed up,this is the little sensor in the airbox assembly.These sensors always give trouble i had the same trouble myself and changed this sensor and then everything was back to normal.

 

Have you checked to see whether the Hose from turbo to TMIC and from TMIC to throttle body are ok and haven't split or come adrift?

Cheers

 

thanks for the replies.

 

I will get a new MAF today. Anyone think there is any chance tha the spark plugs could have caused this?