What could cause a hot start miss/rough idle that clears up?

[luigisho]

there is probably residual fuel in the rail for a long time but usually after 24hrs alot of pressure has leaked back down. Especially if the check valve at the fuel pump is faulty. I had that problem years ago with my GenI and had hot starting issues. The fpr allows a majority of the fuel to flow back to the tank while it's operating. There is more restriction from the spring loaded diaphram in there at wot vs idle, but even then most of the fuel pumped to the rail gets returned to the tank. I believe the check valve retains more pressure in the line over medium and long periods of time, after you shut it down, than the fpr. I'm not an expert, just someone with sho's that have alot of things break.
Also logical guess that the fpr's you checked with vacuum have responded similarly-- makes me guess that they shouldn't all be defective.

 

[jimtash]

OK, got it running again. Still getting a miss at warm start up until the throttle is pressed down and it clears it up. Nothing like before though when it would almost stall out. Runs much better since all the injector connectors have been replaced but there is still that lopey after fan idle present. Put on a spare cam sensor and will run it tomorrow and see what happens. If that doesn't clear it up, I have a spare set of 3.0L pink top injectors to install.

Now a 565 canister purge valve code has come up and no vacuum is in the tank.

Also went ahead and replaced the timing belt again to rid it of the noise that couldn't be taken out with the tensioner. Either it would be too tight and whine or too loose and flop around between the camshafts. That at least is a success. It's a Pronto brand belt which is USA made. The one that was on there was a Dayco BTW. Don't think I'll use Dayco belts again.