I would do the plugs and wires before going that route. Those wires start dying around 100K, one by one. Run it too long with a bad wire, it will damage the coil/distributor.

 

One O2 sensor and an oil pan gasket should be here tomorrow. I have a feeling there are probably 2 Upstream O2 sensors though. I guess I'll change the front one and see what happens. I can't remember exactly which one threw the code once.
After that I'll also pull the oil pan and check the pickup(gotta wait a little while since I just did an oil change). Looks like it's pretty wide open and shouldn't require much work to pull.
I have to go about this the old fashion way and make one repair at a time. It's better to know exactly what was bad so maybe the next guy has it easier.

 

The sealant they use to install those oil pans is like concrete when it cures. Be prepared to do some scraping and hammering. Dead Blow hammer to the sides of the pan usually does it. DON'T use a metal hammer.

 

I wish you wouldn't have told me because I might just not do it afterall. Chipping the gaskets out of the valve covers sucked bad enough that I almost quit after the first one.

 

Well, the upstream O2 sensor did not change anything as far as the oil pressure light. So hopefully I can get to the pan gasket with this longer holiday weekend. Aside from that I'll look and see if I changed the plug wires. If the pickup is not plugged I think I'm going to just give up on this car. I've already been told I should quit wasting time and money on it.

 

On the way back from an hour and a half trip the EGR transducer decided it was going to crap out. So stop-and-go traffic was great with an EGR that was somewhat open. At least that's another piece of the puzzle that I had suspected but wasn't quite sure of. Guess it will be interesting to see what sort of an effect that has on things. I pulled the EGR and it's clean so there is no carbon buildup holding the valve open.

Still waiting on dropping the oil pan though. If I don't get this misfire Check Engine Light issue fixed I might be renting a car for a trip to Texas. I just don't know if this car is capable of an 8 hour drive or not. When the transducer shows up I'll have to hit the interstate and see what happens when it hits 75mph. In the past that's when it's thrown the misfire code. Parts show up Friday so I'll have an answer this weekend. Also picked up a new set of headlights that are not yellow and cracked.

 

EGR is working again. I have not made it to 75mph though.
Does anyone have a correct resistance chart for ECT and IAT sensors? I'm going to check them along with the TPS resistance sweep.
I have been doing some searches and just about every chart is different and by quite a bit in fact. I don't know if there will be a definate answer considering every part manufacturer would use a different brand of thermister.

I have a feeling the occasional low idle speed/oil pressure light is related to the TPS though. Sometimes the car will have a hard 1-2 shift but only when letting off and then going back into the pedal around 5-10mph. The low idle speed can only be explained by TPS, IAC or a rich fuel condition based on the ECT or IAT.
At $50-$75 for a TPS I'm not sure I'm ready to start throwing parts at the problem just yet.

 

UPDATE:
EGR did not fix the Misfire Code. Came on again. I checked the TPS with a meter and it looked good but that does not mean it doesn't have a bad spot I'm not seeing. I still need to drop the oil pan and check the pickup. I'm thinking of stopping by a Mitsubishi dealer and trying to talk to someone in the shop. Could low oil pressure cause a misfire because the valve lash adjusters do not have enough pressure feeding them? I feel like I'm working in circles on this and I don't know if it's a fuel problem causing the low idle/misfires and oil pressure light, or if the oil pressure is causing the misfire and rich condition/low idle speed.
I'll get to it one of these days though.
My list of work around the house is still very long and I have remodel projects to finish up before December. So I have half a basement, a bedroom, and possibly a bathroom to get fixed up before relatives show up.

 

Dont know if you have already, but have you changed the oil pressure sensor? When they go bad, the light will come on at idle and go away when on the gas.

 

Well, codes keep popping up. Now I'm randomly getting a P0403 EGR code as well as the misfire codes.
I did find out with a scanner that the TPS is reading 21.2% with the throttle closed. I'm no expert but that seems like quite a bit. I need to do a voltage test and if the scanner is telling me 21.2% then I expect to see somewhere over 1v on the center pin of the TPS connector. I'll either buy a new sensor or modify this one to get it back down around .7v. Hopefully this is causing most of the problems. I already got told not to spend anymore money on this car so I'll probably start by trying to figure out how to manipulate the current sensor to read correctly and go from there.