OK...Here goes. Bought this farm truck years ago. Body is rough, but only 90,000 when purchased. It has 140,000 now. Shortly thereafter, it developed a good miss at idle. We don't drive it much (4,000 miles/year) so it didn't bother us too much. At speed it seemed to even out fine. The idle has gotten much worse recently. About a month ago, it overheated and my wife has destroyed an engine in the past. She immediately stopped and shut it down. Turned out to be the heater hoses for the manifold. Quick fix, no major issues, fired right back up.

Fast forward a month and this thing is running HORRIBLE. Pulling multiple misfire codes. Begin to wonder if it is related to the overheating or if it has always had the exhaust valve issue and the overheating issue just magnified the problem. Just tried the glove test and there was zero movement. The coolant looks great. Vacuum appears to be good. This truck has a value of less than $1,000 so i'm not inclined to put any major repairs into it. My thinking is that with either diagnosis, the heads need to come off. Am i missing anything?

From code numbers, OBD2, I assume a 1995 or later Ranger, and 3.0l engine since its the 2.9l/3.0l forum

But post year of Ranger and engine size just to confirm

TSB about Recessed exhaust valves on the 3.0l Vulcan engines were only in the 2004 to 2006 model years , but 2003 and 2007 would be suspect In my opinion

You are correct. 2003 3.0l.

I doubt recessed valve issue is the problem, too many specific misfire codes, i.e. 301, 305, 306 usually you get just one, maybe two, and sometimes P0300, but almost always P0316
And also you have the P0351 code - Ignition Coil A Primary/Secondary Circuit Malfunction, which would never come up with valve issue

Cylinders 1 and 5 share Coil A, so 301 and 305 misfire would come with P0351
Cylinders 2 and 6 share coil B
Cylinders 3 and 5 share coil C

This is why firing order on the coil pack is not the same order as the cylinders
1 5
2 6
3 4
or
3 4
2 6
1 5

Those are the Match Pairs that share one of the 3 coils in the coil pack

Make sure firing order is correct, and the WIRES are routed to correct cylinders

I might replace coil pack just on speculation, or get one from wrecking yard, Ford changed connectors for these coil packs a few times so make sure you get one with the connector matching your 2003 wiring


If you want to test for valve issue:
Then I would first remove all spark plugs and do a compression test DRY, get the average
Then add a teaspoon of oil to each cylinder and do WET test

WET test is always higher, but if a below average dry cylinder jumps up much higher that would indicate valve issue in that cylinder

Thanks for the knowledge.....that is a great explanation. I don't mind trying a coil. Just not sure I want to rip off the heads.

You can test coils and coil packs with an OHM Meter, and it can tell you if a coil is bad................but it can't tell you if a coil is good, lol
To operate correctly the Primary coil is a DEAD SHORT, .5-1.3 OHMs, 0 OHMs is a dead short, its why coils get so hot
Its very hard to measure OHMs that low accurately, and when the coil is operating the temperature change can cause a "tested good" coil to fail
Its easy to test coils so worthwhile to do so, because it can test bad and remove all doubt about replacing it

There is a video that shows how
Google: test ford coil pack the easy way