Explorer running rich, rough idle, stalls, etc...

[Jonathan Hopper]

Hey everyone, I have a 2004 Explorer XLT. 4.0 V6 and it was running fine one day, and then the next day, it all of a sudden started running really rough and had no acceleration and the check engine light came on. Checked the codes and got a Manifold Absolute Pressure high, random cylinder misfire and cylinder 6 misfire. I've replaced all the spark plugs, spark plug wires, ignition coil and EGR valve but still not having any luck. It wasn't until I replaced those that I noticed it was running rich. It is blowing some exhaust that smells like gas. I tried listening to see if the fuel pump was working or not and when I turned the ignition on, I hear a small "clunk" and then the normal buzzing of the fuel pump. Any ideas on what could be causing these symptoms? It's just strange to me that it started all of a sudden when the day before it was running fine. Any help would be greatly appreciated. I really don't want to have to have it towed to a mechanic, but figured I'd check here for any advice before taking it somewhere.

 

[vipersinu2]

Hey everyone, I have a 2004 Explorer XLT. 4.0 V6 and it was running fine one day, and then the next day, it all of a sudden started running really rough and had no acceleration and the check engine light came on. Checked the codes and got a Manifold Absolute Pressure high, random cylinder misfire and cylinder 6 misfire. I've replaced all the spark plugs, spark plug wires, ignition coil and EGR valve but still not having any luck. It wasn't until I replaced those that I noticed it was running rich. It is blowing some exhaust that smells like gas. I tried listening to see if the fuel pump was working or not and when I turned the ignition on, I hear a small "clunk" and then the normal buzzing of the fuel pump. Any ideas on what could be causing these symptoms? It's just strange to me that it started all of a sudden when the day before it was running fine. Any help would be greatly appreciated. I really don't want to have to have it towed to a mechanic, but figured I'd check here for any advice before taking it somewhere.

Did your timing chain rattle? Drain the oil and look for pieces of plastic in the oil you drained out, If the oil is free of debris, Check for air intake leak where the plenum meets the block. those Bolts and orings go bad causing vacuum leak.

 

[vipersinu2]

Did your timing chain rattle? Drain the oil and look for pieces of plastic in the oil you drained out, If the oil is free of debris, Check for air intake leak where the plenum meets the block. those Bolts and orings go bad causing vacuum leak.

here is a video of a 99 shoc o-ring replacement, which is very similar to the 04.

 

[Jonathan Hopper]

Thanks Viper! I'll give that video a look. I did not hear the timing chain rattle at all. It ran fine one day, but then just started acting up the next. I'll check the oil too. It's due for an oil change anyway.

 

[Tech By Trade]

Check the harness going to the egr valve behind the loom. Mine was missing half the insulation around all the wires, right behind the loom. Check the MAF sensor as well. It too was missing half the insulation on all the wires. Bad few years of wire for ford. A co worker had the same issue on his focus of the same vintage. As for the missfire, best of luck.

 

[Jonathan Hopper]

Thanks Tech, I'll check the wiring there as well. I did briefly look at it and everything seemed ok, but I"ll do a more thorough check.

 

[Jonathan Hopper]

Did your timing chain rattle? Drain the oil and look for pieces of plastic in the oil you drained out, If the oil is free of debris, Check for air intake leak where the plenum meets the block. those Bolts and orings go bad causing vacuum leak.

What would pieces of plastic in the oil indicate? I haven't checked it yet, but just curious.

 

[vipersinu2]

these engine have timing chain issues, if there was plastic pieces in the oil that would indicate that the timing chain guide could of failed and the timing chain could of jumped a tooth,

You can check for an air intake leak by spraying carb cleaner around those o-rings where the plemtun meets the engine block. if the Idle increase you have a leak.

 

[Jonathan Hopper]

Ok thanks! I'll check those things you mentioned.