'03 Explorer Limited V8. Code P0300 rough idle.

[BobWiersema]

From AutoZone http://autorepair.about.com/library/firing_orders/bl-fo-0838.htm
Firing order is not important in this case. #4 cylinder is passenger side rear.

2003 Ford Explorer AWD
4.6 liter V-8 VIN "W"

Is that the only code? or is the p0300 still there?
It could be just a coil. Does that engine have a single coil pack or individual coils over each plug?

You beat me to the post.

I dont know what that noise is, almost sounds like it could be a bad or stuck valve. I think you should do a compression test on that cylinder.

 

[Don40]

Yes, they are individual coil packs & #4 has a hot blue very strong spark. The P0300 code is gone, we checked it on a different computer this time. The P0304 is the only code we got now.

 

[Don40]

Took my car & reset everything & tested it again. This time I got a P0308 code. So now the only code coming up is this. The other two are gone. I am wondering now if it's a crank sensor, which is what they suggested at the parts store. You can smell unburnt fuel out of the exhaust & it's missing 100% of the time, iddling or highway driving. My gas mileage has dropped from 17 mpg to 10 mpg.

 

[BobWiersema]

Some info for ya.


http://www.engine-light-help.com/P0300-check-engine-light.html

 

[Don40]

Today I took it to Ford to diagnose it. It cost me $217.00 to get a diagnosis. They say that there's no compression in cyllinder #8 & that both valves are stuck open. Ford wants to tear the head off & check to see if there's damage inside. They put a scope down inside the motor & they see that both valves are open which they aren't suppose to be. I brought it home to work on it myself. What should I do next? Any help, I don't want to have to dump 1000's into it. What I'm going to do next is pull the valve cover & see if it's a broken valve spring. HELP!! What are the chances that the valve hit a piston, the guys at Ford said that the scope wouldn't go down into the motor far enough to see. Thanks!!!

 

[Don40]

I pulled the valve cover & both valve springs on #8 looks good. The cam looks good. They both go up & down just fine when you crank on it. I don't know, there's definitely no compression. You can hold your thumb over the spark plug hole, crank it over & the air is going somewhere, it's not coming out the spark plug hole. My guess is it's a bent valve maybe. The rockers go up & down just fine, I just don't get it.

 

[Don40]

I pulled the whole engine out. The valve spring on #8 was broke. The outside of the spring looked good. Once we pulled the motor the back side of the spring is where you could see that it was broken. We had the torque converter rebuilt, replaced the broken spring, tune up. Put the motor back in & it runs great. Except, the front driver & passenger heat blows cold air only, no hot. The back heater works great. That's my new problem, any help? Thanks!!

 

[BobWiersema]

Thats great news.

Sucks you had to pull the engine to fix it but glad to here its running again.

As for the heater, when mine crapped out it was the blend door, but that works the front and back vents so Im not sure on yours. You may want to do a search on Blend Door.

Let us know what you find and keep the rmps under 10K and you wont break any more springs.

Bob

 

[Don40]

I unhooked the ac & the heater has been working fine. I need to fill the ac with freon & hook it back up.
My latest issue is that it has been making a rattling noise at start up. My wife says that it didn't make this noise before & it's getting louder. I started checking it out yesterday & from what I can see I think that the timing chain is loose. Any suggestions? We didn't mess with that part of the motor when we had it all apart.