I'm going to be very thorough in this because I need good advice. I recently bought the Jeep with a rebuilt engine and it had some problems. Now I have fixed most of them and have no cel. While I was fixing it I replaced the thermostat, gasket, and hoses. My Jeep has been reading 160 degrees when it has warmed up, but I thought it was normal since it is the 2.5L and I'm new to Jeeps. Yesterday I noticed some sludge/rust stuff on the dipstick. I got paranoid and checked the oil and coolant and ran the Jeep with the radiator cap off and looked for white exhaust smoke, but it all seemed fine. I did notice that the oil dipstick tube was leaking though along with the distributor gasket and I have been suspecting an intake manifold gasket leak recently. Today I let the Jeep idle for a few minutes and I let the temp gauge go up to 195, but the Jeep started stumbling and I stopped. Yesterday I made sure I filled up the coolant reservoir to full and drove it for about an hour and I lost no coolant. Today when I drove it to the parts store and checked the level it was between add and full.

Now that you know most of the story what could be causing it to act like this? I'm just frustrated with it now.