2000 ford explorer misfiring.

[jamie1606]

Hope someone can help me. I have a 2000 ford explorer. 4x4 v6. One day i started it up and it was running rough. It had real sluggish power. Then the check engine light came on. I hooked it up to the code machine. The only readout was number 3 misfired. I replaced the plug and all was fine. A few months it happend again. I replaced it again and it was fine. Well it just happened again. I replaced it again. It ran good to work but on the way back no good. Light came on again. Hooked up the machine it read number 4 misfired and number 2 bank lean. So I replaced number 4. It still runs like shit rough idle and no power. Give it gas it dogs out but then it'll kick in if i get on it. NEED HELP. If anyone knows anything let me know. Thinking it maybe a vaccum leak or intake leak or o-rings.

[shorod]

You're probably on the correct track with the intake manifold gasket leak, but it's certainly worth checking for vacuum leaks before tearing in to the engine. If you opt to replace the manifold gaskets, you should also consider swapping the fuel injector from cylinder #4 with maybe 5 or 6. That way if you still have a misfire and it moves to the cylinder you moved the injector to, you have a good idea what to replace next to fix the misfire and lean code.

-Rod

[DeltaP]

Check for a fuel pressure regulator leaking fuel into the vacuum hose by disconnecting the vacuum hose. If there is gas in the vacuum hose or if gas leaks out of the fuel pressure regulator with the fuel pump running, the regulator is bad. Not too uncommon to find a bad one on the Explorers/Mountaineers of that year model.

[shorod]

Originally Posted by DeltaP

Check for a fuel pressure regulator leaking fuel into the vacuum hose by disconnecting the vacuum hose. If there is gas in the vacuum hose or if gas leaks out of the fuel pressure regulator with the fuel pump running, the regulator is bad. Not too uncommon to find a bad one on the Explorers/Mountaineers of that year model.

Worth a check, but will a leaking pressure regulator lead to a misfire code for an individual cylinder or a single bank being lean?

-Rod

[DeltaP]

Yeah, usually a random misfire code but I have had it happen several times with engines that seem to change misfire cylinders. It's a worthwhile check easy enough to perform. My input was for what to check in addition to what you said,not to rule it out. I would also check the pcv valve and its plumbing. That fitting in the valve cover deteriorates badly and causes vacuum leaks. Check fuel pressures also.