My 94 2.3l now has 262,000 miles on her and so I've learned a few tricks for this motor. One problem this motor is known for is carbon build up in the EGR, it's 02 Tube, and the throttle body. You can clean the EGR valve PROVIDED that you are real careful with it. First, I'd put a vaccum on the green vac line on it and see if the EGR diaphram is working properly. Short of this you can suck on that thing with your mouth and you should hear the mechanism move in there. Next, pull off the EGR valve and clean it's plunger area with some solvent like throttle body cleaner and a few cue tips. Be very careful not to get any on the diaphram or you'll destroy it. Make sure the port hole is clean and even use some compressed air if you can. Next, remove the 02 tube it hooked to that goes down to the exhaust and spray that thing out with some kind of cleaner. While your at it spray some throttle body cleaner into the port on the intake manifold that the EGR feeds gases to. I used a bottle cleaner scrubber to also scrub that hole out. Not sure if it's good for the motor but I started it up with the EGR valve off and also sprayed more spray in that hole. After all that you've got a pressure control device on the left firewall with two rubber hoses that go down to the EGR 02 tube by the exhaust. Unplug those two hoses and spray and blow them out. One of mine was totally clogged with carbon and was the cause of my error code. I then sprayed some cleaner into the metal tubes on the O2 pipe where the rubber lines connect to. I also sprayed throttle body cleaner up into that module's two hose ports and got a ton of carbon out of there....BUT I don't know if that's safe to do so it's your risk. Anyway, problem solved. If you are in a cleaning mood you can also pull off the IAC solonoid and you'll find a ton of carbon in that air chamber behind it. Clean the IAC's plunger area too. This will improve idle. Of course spraying the butterfly in the throttle body is a good move. I also used a SOFT brush to scrub the throttle body way back behind the butterfly as far as I could reach....Then ran the motor and sprayed more EFI safe throttle body cleaner into the engine while making it rev a bit high. This needs to be done every 30,000 miles or so. Do any or all of the above things at your own risk as I'm not saying it's safe or won't damage something. Just works for me.