After driving my A4 for 15-20 minutes, shutting it off and trying to start it becomes a problem. It will crank, but won't turn over and start. After it cools down for about 15 minutes it will start back up again. MIL light is lit and not blinking.

OK... I have three codes popping up on the old Autozone diagnostic tool

P1250-Fuel Air Metering

PO116-
Engine Coolant Temp Range Perf


P1136-
Fuel Air Metering Code

any thought on this?

 

try checking the fuel pressure regulator, ive seen them before where they dont hold pressure, bleed down and cause problems where it wont start after already being warmed up (hot start). your ect sensor is probably bad(mil) but wont cause your car not to start. your air mass values may also be out of spec but your vehicle should still run (mil). if you have a fuel press. guage hook it up, run the engine(make sure pressure is good) probably 3 bar and 3.5 bar with the vacuum line on the pressure regulator disconnected(those figures are off the top of my head, but that should be a good ballpark figure). shut the car off and let is sit for a few minutes. 5-10. the pressure should stay approx where it was at while running with a slight drop in press. if it drops to almost 0 (or significant drop) the fuel is bleeding back down out of the fuel rail. start vehicle again for a minute or so, shut off and this time pinch the return line off. it should hold pressure. if it does your fuel pressure reg is bad. if it still bleeds down your injectors or other componets could be leaking. let me know your findings. this may not be the problem on your car, but its the first place i would start.

 

Try the coolant temp sensor. It may correct your no start when hot. You may also want to try unpluging the maf when the car will not start. If it starts up you need a new maf, otherwise do the checks that bullitt suggests.