Bucking on Hills AND occassional coolant loss

Hi. I just read a similar post but since my car seems to have more symptoms than the other one, I didn't want to just add to their post.

I have a 2000 V6 Alero with 150K. She's had her fair share of problems but still drives and handles great (when not kinda broken) and I love her and want to bring her back to life.

Basically, here is everything I can think of to help diagnose:

-Just had LIM gasket and all hoses replaced 2 weeks ago due to severe leakage (actually caused my oil filter gasket to blow but luckily in the driveway so I never ran her on empty)
-Got car back on Tuesday the 6th
-I commute 60 miles each way daily, all highway
-Car now has a misfire only while going uphill and only at high speeds. Never happens on town/city streets, only on highway and happens more the colder it is outside. Has been happening since the day I got the car back but some days are worse than others.
-SES light comes on and shows misfire on #2. When reset car will sometimes goes days before SES comes back on. Small little bucks don't tend to set it off but occassionally there is a bigger "buck" and that's what sets it off. Plug and Wire have been visually checked and appear to be fine.
-Plugs and Wires were put in brand new in March 2007 and were premium/platinum parts
-Car has, on 2 occassions. lFirst time it lost coolant was this past monday, about 1 week after the LIM gasket was replaced. I checked the level every time I drove for that whole first week and it never dropped until this past Monday. Added about 1/3-1/2 gal. and then after filled and driven about 70 miles it was perfectly fine still (I panicked and went to my mech. and it was full so he couldn't see where it was leaking since it wasn't at that time) and all day tuesday was fine and now Wednesday it leaked again. Only common factor is below freezing temps on both mornings that is has leaked.

can anyone shed insight into this? My mechanic said it doesn't sound like anything disabling and it should be fine to drive as long as I check/fill the coolant when needed. He can't take the car til Monday but I'd like to maybe know what I'm looking at. Thanks!

If you are losing that much coolant you need to find the issue. It sounds like you could have a cracked head but since you didn't overheat the car that is probably doubtful. I would pull all the plugs and check for discoloration to see if anything is leaking into the cylinders. Try the #2 plug first since that is where the misfire occurs. You may be getting water into that cylinder and it is misfiring. Also try a compression check with the engine cold to see if you get good compression across the entire engine. Sometimes a crack can show up on this test as well. Otherwise do a pressure check on the cooling system to see if you can find where the coolant is exiting the engine.

Thanks for the info... Just an update on the situation. Wednesday night I drove the car home and all was fine, a little misfiring, but that's normal at this point. My and my boyfriend were looking around under the hood and it feels like the wire going to #2 is not as snug as the others and when moved there is wiggle room. We tried to really push it in tight and left it. Thursday I did not have any misfire or coolant loss and drove my normal 60 miles each way.. The SES light actually shut itself off while I was driving (I assume it went a drive cycle with no error so SES went out). Today is a really cold day and being friday in MA, always lots of traffic. Rather than take a chance and worry about making it home, I took someone else's car to work. Mine will be going into the shop on monday and I will let you know what the doctor says :)

OK... so it's been a while and all was pretty well. The mechanic who did the LIM and replaced all the hoses took the car back and replaced the wire and plug on #2, tightened all hoses in car and added some sort of sealer to the coolant. I got the car back about 2 weeks ago and besides a slight coolant loss (he believes possibly SLIGHT leak in head gasket with small amount of coolant burning off due to the exhaust coming out of the car?) it was absolutely perfect!!! No misfires, no overheating or acting weird... she was my baby back again!! THEN... yesterday I was driving to work (it was WICKED cold this weekend and yesterday in MA) and while about 20 miles into my 60 mile drive the SES light came back on. Car didn't act weird, just the light was on. Went to work, sat for a few hours, went to lunch and back to work, sat a few more hours and then off to home. (All while SES is on) About 30 miles into my ride home (All highway, go about 70-75mph) I hit a slight incline and I feel that terrible feeling I haven't felt in weeks, the misfire. I'd say over the next 5 miles or so it would do this on inclines but then it was PERFECT for the rest of my ride home, about 25 more miles. my mechanic came over today when I came home (didn't drive my car today) and checked the codes and I thought it would show a misfire again but it said something about crankshaft positioning sensor and knock sensor? I didn't get the exact terms he used or the numbers because we were outside in the driveway in the dark and it's like 30 deg. or so outside. I definitely know he said there were 2 codes though and one was knock and one was crankshaft. He reset the computer and said it should be fine and I should drive it and see what happens, but I thought I would look into it and haven't really been able to find anything on here about these things. Any insight would be much appreciated because I was finally feeling totally comfortable and confident in my car again and now I'm afraid to drive it and get stuck idling in traffic or something like that. Help! Thanks!!!!!