Hi,
My 94 850 usually has a smooth idle and starts very quickly, hot or cold.

Now the car idles normally for a few seconds, drops maybe 200 rpm's and after a second or two of rough idling, jumps up 200-300 rpm's past normal idle. It stays at normal idle for an indefinite time, anywhere from a few seconds to a couple minutes, then repeats the lower/faster idle sequence.

The same time the above began to occur, starting the car began to take much longer, if it has been sitting for longer than 10-15 minutes. The engine starts, runs roughly for a few seconds, then acts normally, except for the idle problem. The car starts normally if it is started within 10 minutes of being shut off.

The plugs, cap, rotor, air filter and flame trap were changed 2-3 months ago during normal maintenance. The car has 150K on it, I've had it for the past 50K miles. None of the fuel system parts have been changed since I've owned it except for the fuel filter which was changed at around 110K.

The car's symptoms remind me of the 140's cold start injectors when they would start leaking and drip fuel into the intake which would cause the same jumpy idle.

Any ideas on what could be causing the problem?

Andrew Dumas