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Sorry, but this is going to be a little long but I think I need to give some history. Back in the summer I helped a friend move a mattress and box spring. Nothing heavy. Now, he's about 300lbs. We were driving to his house and had been for about 30 minutes when I noticed that the truck was struggling a little to go up some hills. Nothing major, just over passes. I can't imagine that he would have caused that. Then I noticed that my oil pressure needle dropped to 0 and stayed there for a few seconds but the engine temp was normal as rain. I pulled over and checked the oil and yes, it was low. Maybe 3 quarts low. I added and went on our way. We got to his house and unloaded the mattress and box springs then when I started the truck and stepped on the brake it went completely to the floor. No pressure no nothing. I did notice that the engine compartment smelled a little like wire melting but I couldn't find anything wrong. I had the truck towed home. I came out the next day and the brake worked just fine and has ever since. What I've noticed since then is that my oil pressure seems lower than it used to be and that if I'm driving on the interstate at 65 to 70, after a while my oil pressure needle starts fluctuating all over the place. I check the oil and it's fine and the engine temp is fine. So, I'm thinking the pressure sending unit is bad. Yesterday, driving home and after only about 8 minutes of driving, the engine temp is creeping up. never actually gets in the red but right on the edge. 2 minutes later I'm home. In the driveway, I pop the radiator cap and add water until it's full. While the truck is sitting there idling, the temp needle gets a little into the red. I shut it down and let it sit over night. I check the oil level and it's fine. This morning while driving to work in about 35 degree weather, the engine temp gets hot fast and by the time I get to work, it's right at the edge of the red. Normally, since I only drive 3.5 miles to work, the engine would just barely even be warming up on a day like this before I got to work. The other thing I noticed this morning is that at one point, the heater stopped blowing hot air, the temp guage crept up some then the air turned hot again and the temp guage dropped just a tiny bit. The oil pressure was operating at about 40 psi while driving at 2500 rpms. At a stop, the oil pressure would drop to about 25psi. I've never heard the engine ticking even when my oil pressure needle dropped to 0. I do hear a slight ticking when I first start it in the morning but that only lasts about a second then it starts running quiet. I don't know if these two things are related. oh, when I popped the radiator cap in my driveway the water coming out was nice and rusty. this truck is a 91, 6 cyl, 4.0, 5speed 4wd with about 189K miles on it. I have no idea where to start to fix this. NEW: I just went down and was able to spin both cooling fans with the motor off. I'm thinking that should happen.

:banana: :banana: Okay, didn't find anything that addressed my current issue whilst performing a little search, so here goes. My 1992 MJ 4.0, 5-speed with ~80K on it is great to start when cold: it takes like one good revolution of the motor and idles great....problem it is hard to start when at operating temperature....like when I go to start it after 20 minutes at the grocery store. Couple things I thought it was related to that I fixed recently: 1. CPS replaced (slightly improved idle) 2. IAC replaced (no change) 3. New battery (was going bad anyway....slightly improved start...not really though) One thing I keep thinking about is the fuel pressure... I have a gauge at the rail (thanks Hornbro!)...IDLE= 41 PSI, anything greater than idle is 49 PSI. I have larger injectors and the appropriate FPR...the question is this: is there supposed to be fuel pressure just before the engine turns over (key ON)? and just after the engine is shut down...? My situation is that the pressure goes to 0 PSI right after the motor is shut down and when the key is ON and I hear the fuel pump for a second....I heard there was a valve in the fuel pump that could go bad? Any help would be great. Thanks! :cheers:

Never noticed until this winter, heater isn't hot enough. Not really complaining but this winter is rather chilly. My truck's heater get warm it's not broken. It gets hot enough to defrost the windows but not enough to keep the cab warm the entire time. Especially when I'm on the highway it can't heat up the cab enough. Anyone know how to increase the heat coming out. Not just the air flow I mean the temperature.