Hi!
I have a 99 Ford Explorer - w/217k miles. (2nd owner)
I got an oil change 3 weeks ago, tune up 2 mos ago, and new brakes/tires within the last 6 mos, oh, and Brother-In-Law just recharged my a/c last week.

Runs well, and I hope to keep it for another few years, but having problem lately.

Check Engine light keeps coming on - I've taken it in, and they read the code, and it comes up with a misfire. Mechanic resets it, and it will stay off for a few days/weeks, and then comes back on.

Any ideas?

Thanks in advance.

 

Welcome to FTE!

Which engine?

Misfire. Does it say which bank or any other info?

IF SOHC, I suspect a manifold o-ring or crack.

IF OHV, I suspect a valve.

WAG alert in force. ymmv. Good luck, post more info for more replies.

 

Thanks for the welcome!
I'm definitely not mechanically inclined, but I do use google and ehow to try to fix things. Or, just take it to my brother in law, who'll show me how by doing it for me

Ok, finally had a chance to take it to Autozone to have them give me the codes. They gave me C1095 and P0304.

I am not too concerned about the P code, since google tells me it's a misfire. Especially since I did just get the tune up and had all sparks and wires replaced.

The other code is for a hydraulic pump motor circuit. My bro in law disabled my ABS brakes a few years ago, so if it has to do with that I'm not sure why the light is just coming on now. Any ideas or suggestions??

 

If the CEL is coming on and the only powertrain code you have currently is P0304, even if you did replace the spark plugs and wires, is not something you should ignore. The C1095 would not be triggering the CEL.

You have something that is causing the engine to believe there is a misfire on cylinder #4. It could be a bad plug wire, a bad spark plug, a bad coil, a vacuum leak that only effects that cylinder, a fuel injector issue, a cylinder compression issue, an issue with the camshaft position sensor, etc. Your focus for the source of the CEL should be with the P0304 code.

My suggestion would be to start by swapping spark plugs with another cylinder, preferably one that is easy to get to. You don't mention if your Explorer has a V6 or V8 engine. Assuming it's a V6, then cylinder #4 is the cylinder closest to the radiator on the driver's side (in the US). Then find a cylinder with a spark plug wire similar in length as the wire to cylinder #4. Swap the wires (chose a different cylinder for the spark plug swap). Now drive the truck around and wait for the CEL to again illuminate. Have the diagnostic codes read and see if you still have a P0304 or if the P030x followed either the spark plug or the wire. This will help you determine if you need to be looking at the spark plug, the wire, or something specific to cylinder #4.

-Rod