Hi Don, I'm probably getting a bit impatient til the guy turns up on Wednesday with his diagnostics etc, but would a sticking engine valve give the similar symptoms when the the engine gets hot. Iv noticed that it does not backfire anymore and does not smoke as much as it did, not sure why. What it does do now is the revs go up and down when i press the throttle, it sounds like its searching for fuel, or choking its self. Rob.

 

Sorry put it up twice

 

Hi Rob,

An intake valve that was not closing properly due to carbon buildup, a weak or broken spring, a bent shaft, or some other reason, could definitely allow backfiring into the air intake. But it sounds like that problem is gone, at least for now.

One cause of engine speed variation is a vacuum leak or leak somewhere in the air intake between the MAF and the intake manifold gasket. Same symptoms can be caused if the Idle Air Control Valve, EGR valve or carbon canister purge valve are not closing properly.

Have you rescanned the car for any flagged diagnostic trouble codes?

Cheers,

Don

 

Well, finally got my car back on the road, just fitted a new CPS, as the old one was disrupting the timing when it got hot. Just like to say thank you for all your help. Rob.