Hello, I have a 95 940 with 217k miles. When it's under 40 degrees outside, it starts perfectly fine, then after a few seconds it starts loping badly and the whole car shakes and wants to stall. After a minute or so it clears up and runs better. I have replaced and checked the coolant temperature sensor and it seems within spec. I've also replaced the connector. When it's very cold out, if I don't let it warm up several minutes and drive it, when I hit the gas it doesn't move and almost stalls. When it warms up a little bit it's fine. I have replaced all grounds and upgraded a few. I don't know what else to check. The major issue is when it's first started. And help would be appreciated, thanks

 

Sounds like one cylinder is intermittently not firing. Could be ignition or fuel. If you can get the problem to happen without driving, just idling, try pulling each spark plug cable one at a time till you find which cylinder makes not difference.

 

It only happens when fully cold, when it's under 45 degrees F or so. I didn't remove the spark plug wires, but I removed the fuel injector connectors. Each one made the car run worse in the same way, like an actual misfire. When I start it and hit the gas a little to keep it idling at 1000 or above, it runs much better and only lopes a little. If I keep my foot on the pedal and wait, it will start revving higher after 10 seconds or so and then I have to let off a little, and then it will do it again, requiring letting off the gas more. By then it will usually idle fine by itself. But if I don't hit the gas it will lope and will almost stall and keep bouncing as if someone is hitting the gas every second. Like it's a heavily modified V8 racing engine. Also if I try to rev it to 1500 it will shake at that rpm as well. 1100 seems perfect but it's hard to keep it there since it keeps revving higher by itself as it seems to clear out.

 

I believe have a similar problem and think it is due to leaky valve guides allowing some oil to foul cylinder #4.
The problem also seems more persistent in the cold, but clears itself up a minute or two after starting.
As with yours, nudging the throttle clears it up, I believe because the residual oil is burnt off more quickly.
If I park facing downhill, even slightly, the problem is less persistent.

 

That could be a possibility. I recently replaced all the engine gaskets and valve seals, but it seems like some of the valve guides were a bit worn, as the valves would move slightly as I put them back in. I used some valve grinding compound on the valve seats to get them to seal better. I also noticed that the #4 piston is loose in the bore, and the others were tight. I can try parking differently to see if it changes how it runs when it's cold. I am replacing the fuel filter this weekend since I never have before, and I have a long list of other items that need replacing. Thanks for the reply.

 

Pulling the injector cables one at a time with a consistent result shows it is not a fuel problem. It could still be and ignition problem.