I need some ideas.

Here is the short version:
Wifes 98 Ranger, 2.5 had a miss, I now find out for some time (a month).
It will miss when starting out but if you put your foot in it it seems better with more RPM.
Code says missfire on #2.
Truck has 160k, orig wires and the plugs had 40k on them.
Nothing looked wrong with the plugs, I tried a used wire, no better.
I came to the conclusion it's probably a coil, I couldn't get parts last night so I thought I would just take out the plugs and buy new wires and plugs and a coil.

I put the new plugs in, new wires on and of course it ran rough like before so I put a new coil on for the intake side, no better so I tried the old intake coil on the exhaust side. During all this it got almost impossible to crank, seemed to fire out of time, cranking hard and kicking back.
The problem seems to go from bad to worse and back again.

I am sure all wires are correct, good compression etc, it now seems the same as before.

My question is it still says missfire on #2 so should I try replacing the other coil too? Is it possible for a crank sensor to do this?

I have another truck with the same engine and all with 250k on it and it has orig coils never had troubles.

I need to leave town Friday night and need this running before I leave.

Any good suggestions would be appreciated.

 

What did you use to make sure your wires went back correctly on the coil pack? I think one of the repair manuals has it listed wrong.

The coil packs are probably okay, as is the crankshaft position sensor. These should throw a specific code when they go bad. I know the coil code is PO351 and PO352. Not sure about the Crankshaft position sensor, but it doesn't matter since you pulled the codes and nothing came up.

My concern is with the original spark plug wires. 160K and nine years are about the limit I would say. There is probably a light show going on under your hood if you look at light with the engine running. Spark plugs can look good, but they might be broken inside.

 

As I said I replaced the wires and plugs just because I could, no dif.

After much screwing around, new plugs & wires, trying coil packs and a new injector (that I was sure wouldn't help, and it didn't) it still runs rough.
Now it doesn't code missfire (yet)? Maybe it hasn't ran enough?

I took it for a drive tonight with my scan tool. When you are going along it's not bad, like before. When you let up to stop it wants to die (real bad) and then doesn't want to start, sounds like bad timing, then it will finally start.
I noticed the spark advance is crazy when this is happening, it will be idling nice at 8-10 degrees at 800 rpm and if you rev it up and let up (slowly so it won't die) it might try staying at 20-27 degrees at idle (bouncing around) and of course it wants to shake and die. Eventually it backs down.

I am starting to think its either cam or crank sensor, nothing else left. I guess this one has no ign module?
I even tried swaping ECMs this morn just to eliminate it.

Any ideas?

 

Yeah, there is no ignition module on '95+ 4-Bangers.

I've always has a part throttle miss at about 1400rpm. I have no idea what it is, but it doesn't bother me since the truck never cruises there and it never throws a code. I've replaced plugs, wires, coil packs, crankshaft position sensor, and the PCM, and it's still there. Like you, I'm sure it's not the injectors.

I haven't replaced the camshaft sensor since it's not that easy to get to, but your bouncing timing might be related to that. I don't know. The timing belt tensioner might be bad, but I'd think it'd jump time rather than give shaky timing readings.

 

I don't know if a spiking TPS signal would cause a code, but I'd test it just to be sure. What about a compression check just for the heck of it, a burnt valve could really screw with things.

 

This has been a long one.
First I left town and couldn't work on it and then I got sick and didn't get much done but I think I have the answer even though there are some mysteries.

I decided to start all over and checked compression, in the middle of doing it my good gauge went wacky and wouldn’t zero out. (It had previously checked out good on all cylinders). I checked everything out I could think of and ended up letting someone else check it out too. He determined that whatever the trouble was it was mechanical and on #3 because he said he ruined his compression gauge on #3. This explained what happened to mine even though how is still a mystery.

I looked everything over under the valve cover and could see nothing bad, put air in the cylinder and removed the springs and all looked and felt good so as a last resort I yanked the head off expecting something like a loose valve seat or something . Turns out all the exhaust seats are beat out, they look like it has been running on propane (I have much experience with propane).

Odd thing, #3 seat has the least recession and the #3 valve looks like it was running partially open. I am just glad to have what looks like a final answer even though it really doesn’t totally fit the problem(s) it had but I am confident this is the cure.

I am wondering if any Ford techs have seen this before?
Was there a run of soft seats that year?
At 160k they should be ok, my other 98 has 255k and runs great (knocking on wood). The rest of the engine looks great, nice and clean and no ridge at all on the cylinders so with this work it should be better than ever.

Here are a couple photos of the seats and valves.

 

I've never heard of it on the Lima engines. Great follow up.

 

Me neither.
My only other Lima engine was a 370 in a F-700, on propane with hard propane seats it needed seats & valves every 100k. On gasoline they go almost forever.

I ran into a Ford dealership mechanic at the doctors office today and I asked him, he said he had seen a TSB on 3.0s with soft seats but nothing else.
We agreed that I probably just hit the soft valve seat lotto, there was a bad run somewhere and I got 3 out of 4 in this one.
Lucky me