I've had a number of problems with bad idling. Found the Throttle switch set wrong and the Idle air control rotating valve stuck due to dirt.

Got these fixed and it runs Ok now EXCEPT It is very hard to keep running when it starts in the cold morning. It starts with the first touch of the starter and then jumps and bucks, even slight backfiring, and virtually no response to the throttle position.

When it gets warm, in about two minutes, it seems to run fine, both at idle and at fast idle and under power.---- I don't mind waiting the two minutes, but the running is so rough that I am concerned about damage to the engine, as I said, it has a slight backfire sometimes during this warm up period. ----- After it gets slightly warm, I can then shut it down and let it sit for a few minutes, it starts and idles & run fine, or it will start instantly after shut down.

Is my COOLANT TEMP SENSOR bad?

And how in the heck do I get this thing unscrewed??? My hand will barely get under the throttle body to touch the sensor with my fingers!! How the heck do I get a wrench under there? Is there any way to test it without taking it out and doing the "hot water bath treatment as outlined in Bently"?

Thanks for any info that you can give me

bob

Thanks Bob

You can test it at the ECU connector. Bentley's has a chart showing what the resistance should be at various temperatures.

I had the same problem and it turned out the fuel pressure regulator was bad. Too much fuel!! Once the enginge got warm it could handle the rich mixture, but cold it would cough and die if you touched the accelerator.

I just replaced that, fun to get at, coolent temp sensor, use a 3/4 or I think 19mm 1/2" socket becouse the 1/2" is a bit longer than 3/8 so it just fits over the sensor, have that attached to a wiggly adaptor and aprrox. a 12" extension and it will go in through that hole you are using to look in at it just left of the input hose from AMM it will come out fine that way. Iv'e got rough idle on my 91 245 and I replaced the original fuel pressure regulator and the temp sensor and then it started and the idle is great but the real test will be in the morning.

good luck, lenny