I have an intermittent problem with the engine deciding not to idle. It only happens occasionally. Once in awhile upon start up it will start and the idle will drop off to nothing and the engine will die. I can start it again give it enough throttle to keep it running and then it will drive just fine. The next time I shut it off and restart it will act normal. I believe it happens mostly when at operating temp. There doesn't seem to be any rhyme or reason.


Any suggestions??

 

Loooooooooong list, much like War and Peace.

Firstly I would CLEAN both throttle bodies internally. They do Gunk up, and that causes what you got.

The actual idle via the AAV adjuster is too low.

Clogged air filter elements.

Ageing spark plugs in a HE.

Etc, etc.

 

I drove the car daily for the last few days, running errands, start and stop, around town, some freeway and it happened one time. The next time I shut it off it fired right back up like normal. This the way it usually shows up.


I'll try cleaning the throttle bodies.


The plugs, wires, dist cap, rotor, fi harness, all fuel lines, fuel filter and air filters are new. Injectors have been cleaned and flow tested.


Idles around 700-750 rpm.


Runs better than it has since I bought it a couple years ago. Seems to be finally dialed in except for this one little issue. Not a major problem, but it would be nice to take care of it.


I liked this car from the day I bought it and now that it's running like it should I realize what all the fuss is about. I love driving it.

 

If the engine temp sensor becomes unplugged (or has an erratic connection), this could happen. It'll start but immediately die. You can test this for yourself by simply unplugging it (it's the connector that goes to the left front water manifold) and trying to start the car. It'll start but won't stay running.

If you connection is flaky, could be the wiring in the connector.

Good luck with it...

John
1987 XJ-S V12
64,000 miles