Well, not too sure how to figure this out. Thought it was a vapor lock, but reading the related post to a search, it appears fuel injected engines cant vapor lock. If the UltraGauge reads anything over 195 degrees when I shut the D1 off, it will start, but idles rough for a few moments & either straightens out by itself, or I may need rev the engine up a bit 1500-2000 RPM's for a few seconds & it runs fine (well for now). If the temp is under 195 starts & idles just fine. No codes on the ultragauge, but then this issue happens before the ultragauge would see it anyway. I know the VSS is dying, the plugs & wires were just changed & had no affect on the issue before or after the change out of plugs & wires. Ideas?

 

The fuel temp sensor does not report to OBDII port, but the ECU monitors it to decide on how big a pulse to send to injectors to flush out vapor lock bubbles. It is the sensor on the fuel rail, the spec from Rover's guide to injection systems say it should read between 23,000 ohms at -22F; to 290 ohms at 176F. In other words, hotter is lower resistance. If wire is open (connector or sensor) then ECU thinks there is no need for extra wide squirt pulses. May read about 1100 ohms at 104F. Not cheap either.

Unplugged would do it, as things tend to get bumped during plug wire contortions.

 

Oh great keeper of the Discovery knowledge I just checked the connector wiring & it is tight. Then went to AB's website. There are (2) of them, and you are correct... They aren't cheap!! My question is, since they both look the same to me, is the sensor you speak of, the Sensor Fuel Temperature ETC6661, or the Sensor - Air Temperature ERR2946G? Thanks for your help!

 

Coolant temp sensor can cause hot start problems too, but since you are getting good data from it on the scanner.....