Good afternoon members, as I stated back in Feb., I did purchase the 91 JAG XJS V12.I am still in S. Carolina, leaving for Michigan soon. I finally received a plate and registration from Michigan yesterday. I replaced the AAV, hoping to fix a high idle issue. Seemed to help. The car starts well when cold, even starts when hot, but pressing accelerator stalls engine when it is warm. Seems to have a flat or dead spot at a certain point. The car runs well and shows power at all speeds.Any suggestions or advice will as always be appreciated. thank you for this forum. It has been a great source of information.

 

O2 sensors, coolant sensors all critical to providing feedback to the 1980s ECU and ignition ECU.

in my case I replaced coolant probes as a precaution, still had a hestitation bordering on stall when accelerating from a stop, turns out my 02 sensors were as old as the car and utterly ruined, causing the ECU to misread inputs.

I never did fully stall it but if you have good power at speed but not from a stop I'd look into things associated with idle and fuel air mixture to start.

 

The 'could be list' might get a little long....with one stepping-off point being about as good as the other.

Personally, I'd first check Throttle Position Sensor. It gives a signal to command a bit of extra fuel when the throttle is opened, akin in principle to an accelerator pump seen on many old carburetors. You'll need a DVOM to check and replace the TPS.

Another thought is that your throttles are dirty together with worn and mis-adjusted linkages. No special tools needed to tackle this. We can help and/or Grant has some good write-ups that he can pass along when he sees this thread

Cheers
DD