2.3L ('83-'97) Intermittent Rough idle and mis

[93ShtBx]

Hello everyone. I recently picked up another ranger that has me scratching my head.
First off it's a 1993 2.3 2wd 5 speed.
Got the truck drove it a week with only issue being a oil leak. Fixed that after couple days. Then truck left me stranded, missing and no power would stall on any incline. So I installed new coilpacks, plugs, wires, fuel filter.. ran good for a day. Then same issue. So I replaced the fuel pump and sending unit was bad any ways. Truck ran great for 3 days.
Now doing it randomly. Drove 40 miles with out issue making 3 stops one for a few hours. Then after leaving a friend's house it started running pour. Missing back firing and wouldn't go over 40. Then after wiggling some wires on the coil packs she was OK n got me home but running rough again.

No cat. Still has stock exhaust n muffler.
Have replaced all vac lines I can reach.

 

[93ShtBx]

Any info is appreciated..

 

[Chapap]

I had a world of problems when I started. I’ve done the following, all of which were bad and yielded improvement.
EGR valve, solenoid, DPFE sensor
Coil packs, wires, plugs
Injectors
Timing belt
IAC valve
O2 sensor (no noticeable improvement)
Fuel pressure regulator (not sure if that helped)
Temp sensor and basically whole cooling system

I currently run perfectly off of cold start. After a 20 min drive and the engine gets to operating temp, I can barely idle or start. I intermittently get a rich condition code. From what I read, that’s usually an engine coolant temp sensor. The computer doesn’t know that the engine is hot and keeps the “choke” on, causing the engine to run rich. I have a MAF being delivered today and, fingers crossed, that fixes it. I figured every other sensor is new, so I ordered air charge sensor and TPS too just because. If I still have the problem, I’ll be totally out of ideas.

Someone check me on this, but it sounds like our problems kinda sound similar… only happens when hot. I read the most likely culprits are:
1) coolant temp sens
2) O2 sens
3) MAF (not sure about this one, but it’s big in the air/fuel mix department. Will update)

 

[93ShtBx]

Mine does is at random. The other day I drove over an hour straight no issues but after being parked a few hours maybe 4 at most started fine got 1/4 mile and was crap. Comparable issue doesn't mean it's not the same culprits behind our issues. If u find something that works please share lol and I'll do the same.

 

[Chapap]

If it’s an extreme intermittent problem- either perfect or terrible and no inbetween- I’d be worried it’s an electrical issue. Can try inspecting connectors. Maybe unplug various sensors and see if it mimics the problem. Or ideally, someone gives a real answer.

 

[93ShtBx]

Yea that's what I was doing yesterday..
It's like when it acts up its running so rich. Smell of fuel is awful and can't go up a slight hill with out stalling. But after a few mins some times it will be fine and run on

I'm thinking it's electrical just because it usually happens when I'm on a rough road or gravel road. Wonder is its jarring a wire some where.

 

[Chapap]

Well I changed the maf. Got a brand new maf (relevant later). When hot, I seem to idle better and the junction between cracked butterfly and closed butterfly is smoother. I reset the computer but still got rich at part throttle code. On top of that I have O2 sensor not switching is/was rich (which is expected of it’s overly rich… I think) and I get a daggum MAF is/was out of range. Every time I change something, I get an improvement, so if TPS and intake temp sens don’t get rid of codes, I might be at the point of ignoring the CEL.

 

[Chapap]

Oh just dawned on me. When I warm up and ratio goes off, I get bad detonation. Sounds like a rod knock it’s so bad. That may or may not be helpful if you do or don’t do that.

 

[93ShtBx]

Oh just dawned on me. When I warm up and ratio goes off, I get bad detonation. Sounds like a rod knock it’s so bad. That may or may not be helpful if you do or don’t do that.

I get a slight spark knock when it starts running super rich but when it starts running rich it won't even drive with out stalling

 

[93ShtBx]

OK bought a obd1 reader and got a list of faults

172 o2 lean
222 loss of right IDM
223 Loss of DPI circuit
224 spout circuit ground
543 fuel pump secondary circuit fault

I replaced fuel pump. This could be a code(543) from me replacing it while battery still installed?

I'm thinking I need to replace the ICM as 3 codes all link to that.

 

[93ShtBx]

Just thought I would share I replaced the ICM two days ago and so far truck is running way better hasn't fell on its face yet and I've put over 100 miles on it since replacing it. Hope this solves my issue permanently!

 

[Chapap]

Just thought I would share I replaced the ICM two days ago and so far truck is running way better hasn't fell on its face yet and I've put over 100 miles on it since replacing it. Hope this solves my issue permanently!

I finally remembered to order an ICM, then I had to remember to order thermal paste. Just got the new icm in yesterday. The truck runs so beautifully now. I still get occasional hiccups, but that could be due to the black soot exhaust. I must have high fuel pressure. Everything fuel related is new from the rail forward. No clue what’s happening From the rail to the tank.