Check Engine Light/Code Unreadable

[tedrisch]

I have a 99 Ranger 3.0 and the truck started running like crap, then the CEL came on so I took it to three different parts stores (2 autozones, and advance). All of them tried unsuccessfully to read the error code and said that the port might have a bad connection. The truck is running like it might have a bad mass airflow sensor, and I cleaned it out before this problem on a recent tune up with mass airflow cleaner. I think I might have screwed something up in that or the IAC, as i cleaned it too.

Has anyone else not been able to read codes? Should i start throwing parts at it?

 

[tedrisch]

Found out that the cigar lighter was fused with the OBDII power supply and the fuse was blown. Had the code read and cameup with P0305: misfire cylider 5. I just replaced the spark plugs and i'm going to pull it out and see whats going on in there. Maybe I incorrectly gapped that one or it maybe time for new wires, i think they are original and it has 118K+ on the clock. Any other suggestions? My next step is to check the coil pack.

 

[Earl43P]

I've gotten a bad plug, straight out of the box.

You are on track though. Those wires sound due.

 

[smallfarm123@aol.com]

start with the easy thing to replace and go from there. i had to before. i think i spent 150 or so ended up being the maf censor go when i but the K/N air filter on. the oil that comes on it messed up the censor

 

[bogey99]

Misfire

I just had the same problem. So the MAF fixed it? becuase when i looked up the missfire code it didnt include MAF in troubleshooting, there was a seperate code for that. Mine idiling rough and then running normal on and off for some time. I did #5 wire, plug, injector with no luck. Turned out to be a burned exhaust valve needing a head replacement.

 

[tedrisch]

I found the problem to a misfire in cylinder 5 trouble code: P305. I started by diagnosing the ignition system, since i had changed the plugs and may have messed something up.

1. The plug looked fine, just fouled from not firing well

2. I hooked up an ignition spark tester with an adjustable gap like this one:

Iit allowed me to put it at the end of the plug wire and see what kind of spark is getting to the plug. I observed that it was very weak, like less than 20,000 volts, and cylinder 6 was getting well over 30,000 volts.

3. So i knew that the spark was to blame so i went to the coil and measured the volts coming out of the cyl. 5 coil plug to the wire and it was normal, So it meant that the plug wire was bad. I think the wires were original with over 118K on them so i got a new set of Beldens from NAPA: BEL 700224. They work great and went in fairly easy, but those little plastic holders on the valve cover are annoying to remove.

4. I reset the computer and the CEL didn't come back and the truck runs like new.