1996 Honda Accord 2.2 Vtec misfire

[ojlane]

I have a UK 1996 Honda Accord 2.2 VTEC with misfire problems and running very lean on fuel.

It is fine for the first 3 minutes from cold then starts misfiring under load (Gearbox engaged rather than disengaged), this occurs when holding a constant speed or lightly accelerating, this happens up to 3500 revs. If I then accelerate hard or decelerate the misfire dissapears. This fault gets progressively worse the hotter the engine gets.

I disconnected the map sensor for a run and the engine ran fine appart from idle revs dropping but as predicted it ran very rich, this to me would rule out ignition problems, is this correct?

I have changed:- HT leads, Spark plugs, Water temperature sensor, Oxygen sensor, MAP sensor and checked EGR valve also all cylinders are running between 14 and 15 BAR.

If anyone can shed any light on this it would be greatly appreciated.

Many thanks, Oliver

[odyssey2200]

have you have the valve clearances adjusted lately?

VTEC engine misbehave when hot if the valve clearances have been adjusted a bit too tight.

[ojlane]

Not yet, I will check them. Thank you very much