My driver side rear runner gets super cold, so cold that condensation forms on it. I know that this can't be normal and could be a reason for my car not running properly. What could cause this?

 

If it's allot different from the others, then check for a vacuum leak at the plenum and make sure you don't have any open vacuum ports in the rear of the plenum, especially the brake booster hookup. Maybe the brake booster is not holding vacuum?

 

The other runners are nowhere near cold, they feel like anything would feel sitting on top of an engine, lol. I've never had any issue with the brakes and i have check check and rechecks for vacuum leaks. i know it has to be throwing the air temp sensor off because its right there at the runner and the cold temp of the runner makes its way to the back of the plenum also making it cold.

 

Well this is a very odd problem haven't heard of anything like that happening before. My only guess as crazy as it might sound is a blockage in the plenium or the runner itself. Reason being i don't see how its possible to some how not only dissipate all the heat the motor produces plus drop the temperature further somehow to get it cold enough to actually form condensation! However there is a relationship between temperature and pressure and as the higher the pressure the higher the temp must be and the lower the pressure the lower the temperature given a fixed volume. Its kinda the same effect if youve ever used an aresol can and just sprayed it constantly youll feel the can will to get pretty cold as the pressure drops. In your case when the valve opens and the cylinder draws air in if theres a blockage air will not flow air well enough and the pressure in the runner will drop causeing the temperature of the runner to drop as well. Maby a bad dent in the runner could cause this?

 

that makes sense. I already know the plenum is in good shape but when i go to replace the injectors between today and tomorrow I'll have to check out the runner

 

new symptom, pulled the plenum off... full of gasoline

 

Check for a ruptured diaphragm in your fuel pressure regulator.

 

You didn't mention what year car you have. If it has the cold start injector, it may be broken in the Open position, continually spraying fuel. That might account for the cold runner, fuel in the runner, and poor running car.

 

problem solved.... my brand new fuel pressure regulator diaphram ruptured

 

You may want to check out the condition of your return line. If the return line is plugged it will blow the diaphrams constantly as the fuel has no where else to go and the pump will just keep running.

 

hmmmm, i will have to check that! thank you