I appreciate the responses, but we got off track with my previous thread on this subject. I will start again.

After driving for about half an hour and stopping for a red light the car will stall when starting up again. Has done this several times and I believe it is due to the idle mixture being too lean, or no additional shot of fuel to help the start up. Sometimes I can keep the engine from completely dieing by quickly letting off the throttle until the fuel catches up and it will then continue. I get NO code and the car runs great. Idles smooth. And once it gets going again will accelerate great.

Have done a complete throttle body cleaning thinking this would solve the problem. Car has 118,000 miles on it. It is an XJ6 with a 4.0 engine. Otherwise there is nothing wrong with it. But wife won't drive it due to stalling in an intersection.

Please guys. I need help with this problem.

 

No scientific resaoning at all, just some basic "thoughts".

The mixture is basically set by the TPS, and old age is now creeping into these units, which most of us V12 owners will remember with the TPS units on them at about the same age.

Cruising along it is in a position that is relatively "unworn". Once returned to idle, the wiper gets into a very worn section, and the ECU gets a fuzzy signal, knows not what to do, so shuts down.

Secondly, I am thinking the TPS is not "synchronised" correctly, and when the idle position is reached, the signal is out of range to maintain engine activity.

As I said, I may be way off the track, but the TPS is an important prime signal for any EFI system.

 

Thanks Grant,

It just so happens my Indy and I had a long talk late Friday and came to the same conclusin that the TBS might be the problem. I'm going to hook up my scan tool and monitor the TBS closely when I stop under a condition where it might stall. It could be not respong in sync with the pedal initally due to that worn spot at idle. When that happens you have a lot of air and no fuel for a split second. So we are on the same page. Now, it seems to me that I remember that someone lately published pictures of fixing a TBS that was giving him trouble. Going to do a search and see if I can find it. I'll keep you and the forum up to date with what I find for as long as it takes.

Thanks again. You're always a big help.