Hi, any ideas what could be causing my car to use so much petrol? It's using £15 a day to cover about 15 - 20 miles, it stumbles at low revs when the throttle is only half open, but it's fine at WOT. It intermittently has a warning light:

Once it's warm it pops when you come off the throttle... alot.

 

It had a replacement engine abou 2000km, everything was fine then, the engine has 60k on it. It's a 92 NA with a Blitz ECU (mapped to the old engine) not sure if anything else has been changed.

overfuelling like a pig, possibly a duff temperature sensor

I would check your timing. mine did the same till I found out it was 10 degrees out. Moved the CAS to compensate & everything back to normal.

That's a cat overheat light which is basically unburnt fuel is going into your exhaust and igniting. I would start with cleaning all the connectors in your engine bay, especially the PTU, CAS Temp and coilpack connectors. It'll only cost you a couple of quid for cleaner and could quite easily sort you out :)

 

Vijay

Is the an engine bay picture labelling the various connectors I should clean?

Engine by numbers

Gotta be a coilpack connector or ptu connection. 99% coilpack connector though ;)