ROUGH idle

[HMFM Miller]

03 Ranger EDGE 4x4 w/ 3.0l auto.

So today my truck develops a rough idle but I had to go somewhere so I took off. Well 5 miles down the road its missing and knocking like a jehovah's witness. CEL flashing.
Well I get it back to the house and get a code for mis fire on no 5. cylinder. I pull the plug, plugs good, compression check it. Its good too.

I replaced the plugs and plug wires about 20k ago with good parts. So I think it has to be the ignition coil. I got a new one and swapped it out.

Its running better and not misfiring but still has a rough idle and the engine surges. No CEL. Im lost. Im going to check the idle air control valve in the morning. I have a 2hr drive on thursday so I gotta get it fixed.

Thanks Ranger nation.

 

[adsm08]

Did you bother to get the codes reset?

 

[HMFM Miller]

I didnt clear the code with the scan tool but I did unhook the battery when I put the new coil in.

 

[adsm08]

If you unhooked the battery it may run oddly for a day or two as it relearns things. Especially if it has a lot of miles on it.

 

[HMFM Miller]

The truck has 164k on it but I had to rebuild the engine about 20k ago. I had the battery off a couple weeks ago to swap out a terminal, but I understand what your saying. Im gonna hook the scanner back up to it tomorrow to clear out any codes left.

I did get it up on the interstate for a bout 3 miles and it pulled fine under the steady load, thats why Im confused.

 

[adsm08]

Get a scanner on it, don't just clear the codes, reset the KAM. Then take it out on the highway, do a pull from 25 to 65, then let it coast back down to 25 without touching the gas or brakes. Do that a total of 3 times. It will let it relearn the misfire correction profile of the engine. Sometimes they don't always run right when the MCP isn't learned because it's not sure what to count as a miss.

 

[HMFM Miller]

I dont believe my scanner will let me reset the KAM. Its a low dollar type. Thanks for the info.

 

[HMFM Miller]

Well I cleaned the IAC and drove the truck. Drove decent but then the miss came back. No code at the moment. Im at a loss. Injectors maybe? I dont think its a valve because it comes and goes. Its lost power as well.
Help ranger nation!

 

[adsm08]

Sounds like an injector or a wiring/computer issue are the last things left.

 

[HMFM Miller]

Do you think its ok to just swap out the one injector on the cyl that was missing? Or at least the three on that side since I have to pull the intake for that side?

 

[snake]

just swap it with another on that side and see if it throws a code on the new cylinder. You can also dump some 44K injector cleaner in there and see if it straightens it out.

 

[HMFM Miller]

uncle sam has kept me busy the past few days so I havent had a chance to work on it. I bought a new fuel filter, Im gonna swap it out in the morning. I doubt thats the issue but its a cheap place to start. After that Ill move on to the injectors. Its not throwing a code but continuing to miss so Im not sure which cylinder is the bad one, originally it was no. 5.

 

[HMFM Miller]

Swapped out the fuel filter and major improvement. When sludge pours out the filter inlets its prolly time for a change. I guess thats from 10 years of hard miles and a several trips off road, pushing through deep water etc. Thanks for the help gents. Its still not where it needs to be but its going in the right directions.

 

[HMFM Miller]

So my I pulled the the fuel injectors. Theres rust on them? How can they get rust on the inside surface?