I'm having an issue with a rough idle along with my gas mileage dropping about 50%. When I start my car first thing in the morning, it will turn over and sometimes stall, or the RPMs will drop low enough where the interior lights illuminate for a second, but the RPMs will go higher. And then back down again. This process will repeat itself until the car warms up. If I press on the accelrator, the car sputs and sputters at first, but reacts normal once the car warms up. Once warm, the car idles as advertised. I cleaned the throttle body, and this helped alot, but has not fixed the rough idle I've also cleaned the Idle Air Control Valve, MAP sensor, MAP sensor, throttle position sensor and I've changed my EGR valve. I've looked for vacuum leaks and haven't found any. With the car running, I've sprayed Carb cleaner all around the engine to try and find a vaccum leak, but nothing. After all this, I dropped some SeaFoam in the gas tank, followed by some 93 octane to a full tank, and, as stated earlier, the car will run/idle fine once warmed up. But my gas mileage is terrible. I normally get about 300+ miles to a tank. I'm at half a tank, and havn't even reached 100 miles yet! I think my IACV is bad. I will diconnect it, start the car, and it will idle at approx 1200 without a hicup.I'll turn the car off, connect it back up, start the car, and the rough idle returns, but could the IACV really be the cause of such a drastic change in my fuel economy? I've also pulled my plugs and to make everything even more confusing, it seems the car is running lean. My plugs had a chalky, greyish look to them. They were not "wet" at all.
Tuesday, February 28th, 2012 AT 12:47 AM