Oil Pressure Switch, Gauge, and Power Steering Pressure Harness & connector. Another common part baked on every 3s. Replacement plugs from mitsu are not avail. Use a 4 pin trailer harness, or 3 pin, or you can find any other multi pin connector to replace this one with. This can cause false readings of oil pressure with stock sending unit.
E-Brake Floor Plate. The area the ebrake handle is bolted to is real thin sheet metal, ive seen more than a handful of cars where this has had to be re welded, or modified in some way due to pulling the ebrake right out of the damn floor. MAke sure if you weld, or cut this area to coat it with a corosion control paint/sealer.
PTU & Ignition Connectors. Ive noticed these like to corrode with just about everything else on the 3s under the hood, but these can get VERY problematic. Use a sharp knife, sand paper, dremel sized wire wheel, ice pick, etc... Get the corosion off, can help with spark blow out, and stumbling.
Is your Cyl 3 & 6 coil pack burning up? Car running on 4 cyl? Remove plastic loom and tape going from PTU 3 wire connector, to Ignition Coils 4 wire connector. You will find that a small gauge black w/ white stripe wire goes back down the harness, and a blue w/ yellow stripe 12-14awg wire comes back up the harness, but for the other two ignition channels they go straight to the coil from the ptu. Yup you guessed it, cut that damn thing and splice back together. Those two wires go to the blue connector at the passanger strut tower, they are used for engine rpm detection for diagnostics, atleast it says in the manual. Its fairly easy to diagnose ignition problems by just pulling the wire while the car is running. If you get shocked, it works! But no joke, That short recently left duTTch's car inoperable, and burned up 3 coils in the process of trying to eliminate different parts as being a culprit. This can also be a possible cause to spark blow out due to the resistance of such a long wire, as well as corosion of the wire leading to poor charging of cyl 3 & 6 coil.
Dome light not work on one door? Lights flicker with one door open? Headlights not shut off on your 1992+ 3s? Factory Alarm doesnt trigger? Take door pin switch out of frame, loosen screw on back, and spread the little fang looking teeth out some so they will touch the frame of the switch. may also need to be cleaned due to corrosion on copper.
Drive Shaft Inspection. Check carrier bearings, anything more than 1/2 inch of play, id start getting suspect about. DS problems start to occur @ 90-120K. Also check U joint on the front of the shaft that goes to the Tcase, if this is worn, replace shaft, or take shaft to a DS shop to have dodge truck u joint/yoke welded in place. This personally stranded my ass when i destroyed the U joint and bent the yoke.
Turbocharger Oil Supply Lines. 120K? New turbos? Replace them, they arent expensive. If one of these small lines cloggs, bye bye turbo. Run carb cleaner through oil return lines to clean them out if engine ever spins bearings, or if they are off the car for any reason. Make sure to blow them out as well.
Stock Alarm go off for no reason? Passanger side headlight bucket, see that switch with the rubber gromment on top? Bend it up a bit.
Door panels off? Go ahead and use white lithium grease on the lock mechinisms/linkages. Prevents locks from sticking in frigid temps.
Window Regulator Inspection. Older the cars get, the more this becomes an issue, the white plastic peice on top likes to crack allowing the window to stick or fall down. May also want to grease this if the door panel is ever off.
Rear windsheild wiper blowing fuses? Replace the switch, plastic tab likes to break allowing a short to occur when activated.
Syncros starting to grind? Throw some syncromesh, syncromax, or other synthetic gear oil in the trans. This will give you some more time.
Transmission Output Shaft inspection, Transfercase Input Spool Inspection. Got the Tcase off? check the splines for wear/twisting, replace if needed. Use grease on these as well to control corrosion.
Intercooler Punctures. Make sure periodically that you check the IC's visually for any holes that may be caused by large rocks.
Radiator Inlet Inspection. Check this every time before you go drive, especially with a 99 front end. News paper, and trash likes to get in the large openings blocking the A/C Condensor leading to overheating issues.
Fuel Tank Corrosion Inspection. Take passanger rear tool tray out of trunk, remove gray access cover, spray WD40 all over this bitch to help stop corrosion of the bolts that hold the sending unit to the tank.
Rear E-Brake Pads. Check these any time your changing your rear brakes out, esp if you use the ebrake for anything other than parking. Higher milage vehicles will need to pay attention to this as well, atleast inspect every few brake pad changes or if the ebrake starts to not hold very well. May need to adjust linkage on ebrake handle. Accessible by removing center console and tightening cable with 10MM wrench.
Steering Wheel Clock Spring. If your steering wheel lights flicker when turning, horn doesnt work when turning steering wheel, cruise control malfunctions randomly, SRS light is on, Id advise replacing this. This is a saftey critical item. Service only with power removed from the car.
Cruise Control Vac Hose. This likes to melt on TT cars often causing Cruise to not function, run new hose from vac pump under throttle cable junction box, to throttle actuator behind tbody on firewall.
Fuel Injector Seals. I advise at minimum every 60K miles replace the rubber orings on both the top and bottom of the injectors. This can turn into a fuel leak and a fire, or a nasty boost leak.
Fuel Rail O-Rings. These are on the crossover tube, Stock FPR, and Feed line. Replace every 60-120K as a prevenative measure. Any time any of the mentioned items are removed from rail, replace oring as well.
Throttle cable tension. If you've had the throttle cable loose, make sure you set the tension correctly. it should be taught. Touching it with the finger does not move the throttle plate with a light touch, but any significant pressure, throttle should move.
Idle Air Control Servo. 120K+ failure prone part. Stealth316 has testing proceedure.
Ignition Coils & PTU. 120K+ failure prone part. Stealth316 has testing proceedures. Can result in spark blow out, as well other performance issues.
Altenator Charge Wire Corrosion. large gauge wire at altenator, can have corrosion on it. Do not loose plastic spacer between connector and altenator, fire will occur if this spacer is not put back in place. This can be a source of poor charging/voltage issues.
Vehicle power/Battery Charge Wire. White 12awg wire going from fuse box to battery, check for corrosion. Can lead to charging/voltage problems.
Oxygen Sensors. Poor gas milage? Overly rich exhaust? o2's tend to start becoming innacureate in the 50-70K range, if you have 120K on them go ahead and yank em out and replace em. your gas milage and spark plugs will thank you.
Coolant. Replace it atleast every 15-30K, or every other year at minimum. Use 50/50 mix of gycol/water, or DISTILLED WATER w/ Water Wetter. Avoid tap water at all cost. If coolant smells burned, appears to be a wrong color, contains rust, or is very murky, replace it. Tap water will lead to corrosion of cooling components due to minerals and other contaminants.
Rear Differential, Transmission, Transfercase Oil. Replace every 15K, or more often if the car is beaten on alot. Ive seen alot of cars with very nasty rear end fluid, this is not healthy for the VCU. When draining Transmission fluid, watch it drain, make sure no black goop comes out, if so VCU has shit the bed. Check Transfercase Drain Plug for excessive metal on the plug.
I'm done for now. These are all issues ive personally encountered in my past 5 years around the 3s. Id recomend checking some of the items in which are easily inspected to be done atleast every 15K, Some of the items I have posted should be checked more often, but it varies due to driving conditions, cliamte, driving habbits. Some of the more complex items to be checked if a problem arrises, or if doing serious maint of the vehicle. If buying a 3s, or doing your itnitial inspection on your car, id go over probally everything posted in this thread that you feel comfertable doing. Alot of personal experiances are going to be posted and emphasized on. I obviously left out quite a bit as most of it was already mentioned in this thread. If there is something you are not sure you want to attempt, or doubt your ability to do correctly, please seek help from a knowledgable 3si member, or mechanic. I am in no way liable if you screw up, or information posted is not 100% to detail. Not responsible for damages in any way
. Sorry had to include the disclaimer.