2002 3.0 Cyl 4 misfire/rough idle
Hey guys, just bought a 02 Ranger that had the transmission go out on it. I bought it for 1700 dollars. At the time, there was no CEL or rough idle that I noticed, but it couldnt be test drove. I towed it home, and had the transmission fixed. After picking up the truck, it threw a cylinder 4 misfire code and had a rough idle It throws the code when it has a long idle, such as a long light. It does not seem to throw the code when driving. The truck also bucks and stumbles right around 3k RPMS. I have replaced the spark plugs, the wires, the coil pack, the fuel filter, the injectors AND the Cam position syncro. It still has the same symptoms. When I pull the boot off cylinder 4, there is almost no change in how it runs. So cylinder 4 seems to be pretty much useless. I'm thinking that its a valve or headgasket issue. Going to run a compression test tomorrow. Any thoughts or advice?