Hi All,

I've a 03 WRX (blob) PPP that has a weird hot running problem. After 20+ mins of driving, the engine cuts for a split second giving a horrid lurching feeling.

It only does it when on light throttle below 2k rpm (worst about 1k to 1.5k) and on sustained boost over 3.5k rpm. Short blips through any part of the rev range are fine. If it's kept at a steady 2k to 2.5k it will run flawlessly.

It's worse on hot days (especially bad at the minute). If it's left to cool for a hour or so it will run fine again. Filling the tank with (cold) fuel doesn't seem to help.

This started towards the end of last summer, but in the colder weather it wasn't a problem for the length of my daily commute (28 miles each way).

I've had the computer checked for any codes by the local dealer and it was clean, nothing at all. But the engine management light flashes every time it jolts!

Car specs as follows:

2003 WRX PPP wagon
104k miles
New PFR6B plugs (gapped to 0.65mm) (Tried PFR7B, no difference)
New genuine coil packs
New genuine MAF a month ago
Fuel pressure regulator replaced with OEM second hand part
IACV cleaned
Standard airbox & filter
Run on BP ultimate/ GO super (best we can get here in NI


Again, no codes even though the engine management light flashes. The dealership didn't persist long enough for the fault to come up.

I have a feeling that it's some sort of vacuum/boost leak that's causing it, somewhere that opens up when it gets hot. It does sound rather "whooshy", if that makes sense. Like the way an induction kit sounds, but on the standard airbox.

I've tried searching on every forum under the sun, and cannot find anything else like this!

I've the car booked into a better dealership next week, but any pointers on what to look for would be much appreciated!

Thanks,

Steve