My 1993 Pickup 2wd (22re) has been idling rough recently and I took the IAC valve out, cleaned it, replaced all the gaskets, but the idle is still rough sometimes. I am 99% sure my idle speed is set correctly. I have a new TPS, water pump, and AC compressor. It doesn't seem to matter whether AC is on or not. I also have an LCE cold air intake (not sure that impacts anything), and I advanced the timing by 3 degrees which seemed to help the tiniest bit. I'm thinking of getting the block off plate kit from LCE to eliminate as many vacuum lines as possible. Has anyone else had this problem, and what did you do to fix it? Thanks.
Check for vacuum leaks and leaking plug wires, maybe the distributor cap and rotor need changing. What do your plugs look like? Those are the most simple things to check. From there check your trouble codes. I have the LCE "cold" air intake, not sure how that could cause the rough idle. Thing really just makes it sound throatier. Unless the installer is a total dweeb. Improperly adjusted TPS can cause issues. Somewhere down the line did you overheat the engine? Number of miles on the engine? Injectors need servicing? So many ways to go. Start with vac leaks and a tune-up.
I have around 205,xxx miles on my motor. Never overheated. Not sure how old the distributor cap and rotor are; I'll check on those today. Also not sure how old the injectors are so I'll probably go ahead and get those serviced and replace the fuel filter. I will probably just go with the LCE Pro Tune up Kit. It almost sounds like it is misfiring at idle at times, so I'll adjust the valves as well. Thanks for the input. I'll keep you updated. Edit: I also have a crankcase breather. Not sure if that would effect anything. (Yes, I capped off the vacuum line)
Crankcase breather? Open to the atmosphere? Could be allowing air into the intake tract through the PCV system.
Try reconnecting the PCV how its supposed to be. Did you change anything right before it started acting up? Like replace a part or something. and dont just throw everything LCE has in their catalog just to try to fix it,
If you have an inductive timing light clip it to each plug wire one at a time. Squeeze the trigger and watch the flashes. Makes it easy to determine if the miss is confined to a specific cylinder or uniform across the board. That and do a vacuum test using a manifold port.
For a bad ignition wire I like to tell people to run their hand along the wire and kinda bend it around as they go. When they ask how they'll know if the wire is leaking I just tell them they'll know. Fun to watch 'em do it! Seriously though, run the engine and, in total darkness, watch the wires. If you have a bad wire you'll see an arc where the wire is bad. You can also use a multimeter to check the resistance in the wires, but that's not always that accurate.
