I have a ‘93 pickup with the 22RE. Having a very weird issue with the engine. The truck starts fine every time, hot or cold, summer or winter. As it warms up, temp needle about 1/4 inch from full cold, it goes through a very rough period. Sounds like it’s only running on 2 cylinders, smoke, and smells rich. It will stay running by milking the throttle. After about 1-2 minutes of this it runs fine and will continue to until it’s shut down and cools off.
The fuel pump and filter have been recently changed. Since the problem started I have changed plugs, wires, and MAF sensor.
I want to sell the truck but need to get it sorted first. Any ideas or troubleshooting would be greatly appreciated.

 

Sounds like one of the water temp sensors- one feeds the cold start injector and one the computer.
My guess and place to start looking is the cold start injector time switch. It's not turning off as the engine warms up and dumping in more fuel than needed in the process.
Cold start injector time switch on the left (black) and coolant temp sensor on the right (green)
Could be just bad connection.
Try disconnecting it when the problem occurs to see it that stops it.
.

 

In think this is a great suggestion above. Time is related to temp in car engines. I have had a temp sensor on a Honda fail within its range and suddenly the car would think it's -30 out and kick into high idle to compensate, seemingly possessed. Hope this fixes it. Let us know.

 

Thanks JoeS. I also thought it was temperature related and possibly something to do with the cold start injector but I don’t know the makeup of the system. (Now I do). I unplugged both connectors(they look fine, wiring too) reconnected and ran it this morning. After it ran for awhile, I unplugged the cold start injector sensor and it seemed to run fine when I gave it throttle. I’m going to check the resistance of the sensor tomorrow morning.
The problem has been so inconsistent that it’s hard to know if what I did helped.
We’ll see. Thanks for the ideas. I will keep you posted.

 

Inconsistent issues are a pain. Just have wait for it to act up the pull the connector to see if it stops. Hope that is the problem as an easy fix.

 

sounds ok, except that the CSI only operates when the temp is below a certain threshold AND the key is in the "start" position. the CSI does not inject fuel into the upper plenum when the key is in the "on" (run) position. as soon as the key is released from "start", the CSI stops injecting (spraying) fuel.

 

Changed the engine coolant temp sensor yesterday. First start and 20 minute drive seemed ok…. we’ll see.

 

4 starts and 20-30 minute drives and it seemed ok.
Until this past Sunday. I tried to start it and it cranked over but didn’t start. I had to give it gas to get it running. After the hard start and 2-3 seconds of rough idling, it cleared right up and road tested fine. Totally different problem than before. This seems like a cold start injector problem to me???

 

Have you sold it?


 

Not yet. It’s been running good but there’s a few more things I want to do beforehand.

 

Run a can of Seafoam in each of the next couple of tank fill ups. Clean the fuel system. I had a rough start/idle after warm running situation that cleared up after running multiple cans of various fuel system cleaners. Think it might have been a stuck injector. Now no issues.