My 2004 RX8 won't start when the engine is warm, when its cold it starts no problem. If I drive the car till it at operating temp and shut it down I have to wait an hour until start it again

I suggest you check for trouble codes with a code reader. When the engine reaches operating temperature it goes from open loop into closed loop control, which relies on a readings from a number of sensors (particularly O2 sensors) to adjust fuel and ignition. If this problem is being caused by a sensor or computer problem, you should see the trouble code and you can go from there.

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audi tt sensors 2004 audi tt coupe windows roll down hi all only new to forum 2001 ...2002 audi tt purchase advice newbie looking to get a tt. ... Used on cold starts towarm engine and cat faster. .... replaced and sending my car into limp mode. my ac just shut off one day and will not turn back on. the esp in the car is stuck off.

run fault codes for faulty sensors. Check coolant level at the radiator cap (not the reservoir). There is a sensor that is shutting down the engine from an over heat situation.

sounds like low compression at start up do to piston slap and not alowing car to warm up over the years before driving off. 3.1, 3.4, 3.5 motor pistons are exact size at operating temp there for cold temps at start up cause the pistons to slap the cylinder wall.. Gm engineers did this to reduce operating temp while driving by lowering friction in the cylinder. problem is most people these days start there cars and take off down the road..my suggesting would be to check piston compersion at operating temp and see if it meets spefications for ur mottor before replacing any other parts...

Friend, you have a faulty temperature sending unit. Change THAT and you'll have this problem no longer. The temp sending unit, when cold, will put the engine, by the computer, into cold start mode, the engine starts getting a bit more fuel until is warmed up, then the sending unit tells the computer it's warmed up and shuts down the cold start mode. Only makes sense, Right?

Ok, time for car school. The vehicle is operated by the computer, every electrical concept that is. When the engine is cold, it starts fine because the computer has placed it in "cold start mode", putting more fuel into the engine than normally would until Once the engine is warmed up, a temperature sending unit or temp sensor tells the computer to change to normal run mode. IF said temp sensor is faulty and is not telling the computer to make said change, it stays in cold start mode, still dumping excess fuel in the engine that is now not required, cause it's warmed up. Like keeping the choke closed on older vehicles. Now I think you can answer your own question, when this no start action is happening after warm up and it always starts fine when cold, what's the first thing you check ? Right, the unsuspected temp sensor. Change that and no more start problem. Have a wonderful day. Glad I could be of service.

HI check your air filter make sure is clean, replace spark plugs if fault whit fuel ,if thats the case also replace your oil and filter

If there are no vacuum leaks, change idle control sensor.

check coolant level ,must be low ,chck for coolant loss

Check to make sure your thermostat works right by monitoring the warming up of your engine. With a completely cold engine, start and run the engine for a few minutes, then put your hand on the top radiator hose to monitor if and when it gets warm as the thermostat opens more and more and note the gauge reading( if it works) the top radiator hose should be unbearably hot within 5-8 minutes. If the therm. opens right it should close right aswell, staying open a little while eventhough the radiator may have cooled may be what you are experiencing causing the rapid cooling and is nothing to worry about. The Hose should not get warm very soon after starting the engine. Regarding you gauge, lets take one step at a time, verify proper op. or the therm.