[SPD1973]

I have a 30EA code - NOx Sensor, this causes rough idle at cold and hesitation also. £350 quid part, but not an issue to throw it into limp or EML. The NOx should be deleted from these cars as they are not used for petrol anyway. I think replacing it with an emulator replacement is likely the best/cheapest course of action.

Before you fire the parts cannon at your car, only treat codes as a guide to look at, get someone with the experience and scope, to truly find the fault with the vehicle. Cheaper in the long run.

[jwilalex]

Two things could be causing your reoccurring oil pressure light that disappears after engine off for a while:

1) Residue from broken timing chain guides (whether current or historical that wasn't removed) living in the sump and getting hoovered up into the oil pick up... restricting oil flow. Engine off it sinks back to the sludge again only to be hoovered back up again later.

2) Balance shafts on the oil pump being out of kilter are known to cause issues.

I can talk from experience here on both accounts.

A possible option for continued rough running/misfires centres around the vanos hubs seeing as you've pretty much done all the other fixes. If either hub is weak or failing it will cause misfires. Again experience in this area also.

As it happens mine is in the dealers waiting for a brand new engine as it died a couple of weeks back. Warranty (BMW extended) have approved but there's a delay in provision till 18 Oct. Anyway, for anyone thinking whether warranty is worth it or not, all the above mentioned issues (and a few other expensive not listed) plus the pending new engine have been sorted by warranty. The new N43 engine will cost me £100 excess. By the way mine is a 2009 and that dead engine had 126k on the clock