The engine in our 1990 240 has run very well in the year we've owned it - more power than our '85 245 ever had, no oil between changes, etc. Only problem up to now is need to occassionally add coolant - with no leaks visible.

However, this week it started to miss at cold start-up - and now misses severely. The engine smooths out when it warms up - w/occassional miss at fast idle. It ran OK on a brief road test. I cut road test short because the engine suddenly developed a noise valve(?) - loud enough I could hear it in passenger compartment. Prior to road test, I had attempted to isolate a bad cylinder by disconnecting fuel injectors one-by-one. No single cylinder seemed to be at fault (engine ran worse each time I shut down an injector). Engine also stalls when AMM disconnected - which is what it's supposed to do, right?

I'd say it's a blown head gasket (coolant leak & exhaust is very wet) or bad valve (listening through a big screwdriver, it seems to come from #1 cylinder), BUT this is inconsistent with results when I disconnected injectors. I plan to do a compression test this weekend and would welcome any advice from the Board.

New parts/work in past year are: plugs, cap, rotor, engine position sensor, O2 sensor, idle motor + cleaned throttle body and checked valve clearance.

John, aka analog dad, currently maintaining '93 940, '90 244, '85 245 and missing my old 244Turbo.