P0306 code. I've been dealing with this code for about a month. Truck idles just a little rough. It started just ever so often and gradually has gotten worse. At first would only come on after letting her idle for several minutes. Now it comes on in about 45 seconds. I've replaced the plugs, wires, cap, rotor, 2 O2 sensors and installed a new updated Spider injector assembly. If I start it up and just drive the SEL will not come on. Truck runs great up and down the road just rough on idle. I've done the cheating compression test, unplugged the coil and turned the engine over, turns over smooth with no hicupps. I did the seafoam treatment which didn't help. Also has a new fuel filter. Truck has 250k miles on it. Cats were replaced 17k miles ago and fuel pressure regulator at 221k miles. Burns about a quart of oil every 3k miles but doesn't smoke. HELP!!!!

 

I've also pulled the EGR off and cleaned it. It operates as it should and wasn't that dirty. I've cleaned the MAF sensor several times. Truck has aftermarket exhaust and a cool air intake with a DRY donaldson filter. I'm also running a Superchips cortex programmer on Performance.

 

Time for real compression test and cylinder leak down test!