Long time lurker/searcher for knowledge - thanks to all who have shared their wisdom/knowledge with this group. This is may 1st issue I haven't found an answer for - and yes, I have searched - maybe not for the right thing as I haven't found anything sinmilkar - and I know I'm not the first person to have this issue.

Truck - 1991 Ranger, 2wd, 2.3L 4 cylinder, 140K miles

Problem - I've gone from an occasional miss to a fairly consistent 2-3 cylinders firing. The real issue is this is an intermittent problem - it comes and goes. Some times it is 3 cylinders, sometimes 2, sometimes 4. I've pretty much convinced myself it is an ignition problem. I've found the measurement procedure for testing the coil packs - but don't see a way to do it in situ - to me, gaining access to the test points on the coil pack is going to mean removing them. I did find a test procedure that is supposed to evaluate the ICM - but it requires access to the wiring with everything connected - and I can't see how to do this on the intake side with everything assembled.

So - a couple of questions:

1. Is there a "static test" for the ICM? I've found some discussion that seems to imply the most common cause for losing 2 cylinders is a failure of the ICM. As this is the most expensive component in the system, I'd like to be reasonably sure this is the issue before just blindly swapping parts. Is it reasonable to expect this part to operate intermittently?

2. I've had experience with individual coils getting flaky when hot - this seems to be the other way - a bit more likely with a "cold" engine. Whenever it occurs, if I keep the vehicle moving and some throttle, it will generally "clear" and return to proper operation - for seconds to the next start.

3. Anything else to check? I have replaced the 6 "easy" plugs - while I've read that it IS possible to change the last two plugs on the intake side without disassembly, I haven't been able to get enough access to even get the plug wires off, much less get to the plugs. If I pull the intake manifold ro get to them, I'll change the wires at the same time.

I'm open to any words of wisdom/advice or suggestions.

Jeff Rees

 

I think there is a current and somewhat recurring problem with water in the fuel supply in NW GA. I have noted an intermittent misfire that does not last long, but definitely affects how the engine runs. My ignition is much simpler, one coil, one set of plugs & wires, and if parts failed, I think it would be more constant. When the miss occurs, it is like a dead miss on one or more cylinders. When I press the clutch to shift, the engine rpms drop a LOT more than I have been accustomed to, making shifting smoothly more difficult. It runs but seems down on power.
I added "Heat" to the gas tank when down to 1/4 full, and that seemed to help a lot. I think the 'up to 10% ethanol' is being exceeded, and the ethanol is mixing with water from the storage tanks. The water will be absorbed by the ethanol, and will burn with some reluctance.
I may be wrong, but it sure acts like it is trying to burn water. This started after buying fuel at a station I never used before. The Heat made a big difference.
Tractor Supply had it for about $2.

 

I had a similar thought - I had purchased fuel form a different than normal station before all of this started - but I'm on the 3rd tank now since then, with some acetone added to pick up water and Seafoam and fuel tank treatment added - if anything it has gotten worse. I have not replaced the fuel filter - it is about due anyway, so may try that also. The intermittent aspect would support that idea as the engine picks up contaminated fuel - but I would have expected the volume to have resolved, or at least improved the situation.

Still an easy/inexpensive approach, so I think I'll try some more.

Jeff Rees