engine management problem????????????

[ben doodar]

i have a 92 nova gsi, with the coil pack rather then distributor. its a standard engine, bar an exhaust and filter but that wouldnt make any diffrence. on the over run 4 a short while i.e goin down a bank in gear, the engine management light will come on and then run really ****, knock the engine off for a few seconds and bump it again and it will be fine, until the next time u do it. its fooking annoying me. i took it to mikeanics in congleton, left it with him for a bit, n he said it was not giving a fault code but he did test it without the light on, now id of thought it would of needed the light on to give the fault code? has anyone had this before? can any body throw a few ideas my way?

[craig green]

It should store any fault codes.

You say it plays up on over run, down a descent?? My guess is a crumbling cat internals that suffocates the exhaust system when aimed down a hill.

If its got a decat, I'll shut up. Seen it happen on an Astra GSi though.

[Mike]

If its got a decat, I'll shut up. Seen it happen on an Astra GSi though.

Aye, same thing happened to a mates Rover 220 Turbo.

[ben doodar]

yes it has been de-catted but it is a good point, the front box on it is crumbly n rattly. i do have a new mongoose exhaust to fit when i eventually get the car back together so il see how i get on. it will also do it if ur on a level road and cum down through the gears, maybe il try a new lambda sensor aswell.
thanks.