Mechanic help, Heater/Coolant system

[Woodchuck]

So finally had it in and out of the shop for a day and a half. I let them know how serious I was and filled them in on some new developments, like for the first time, it overheated on me. Not bad, I saw it coming as the temp climbed like it haddn't before. So I got off the road before it hit high enough for the warning light to start going off.
They said they ran the test again for hydrocarbons but didnt came up negative. After trying a few things, they couldnt get it to overheat at all to even a small extent for a while. He said when they finally "copy catted" the conditions where it overheated on me they got the temp to go up to about 3/4. Then they tested again, and only then did it come back positive for hydrocarbons. And they said they hooked up a hose to the reservoir and got about 5 lbs of pressure back. So they said its a headgasket, not completely shot, but that it has enough of a leak to do what it has been doing. They quoted me $1,900 + tax.
Because its a high mileage vehicle, I dont have much money into it at all, and I have a clean garage (finally), and a spare vehicle for the meantime, I am going to tackle it myself. $300 in parts and a 4 day weekend coming up.
This is kind of what I expected to find out, I didnt want it to be the case, but oh well, even after all this I will still be less than $1000 into the vehicle, including purchase price. So I am not gonna cry.
Thanks to everyone for their input!

Take the time to get the heads surfaced. 

[jackelope]

So finally had it in and out of the shop for a day and a half. I let them know how serious I was and filled them in on some new developments, like for the first time, it overheated on me. Not bad, I saw it coming as the temp climbed like it haddn't before. So I got off the road before it hit high enough for the warning light to start going off.
They said they ran the test again for hydrocarbons but didnt came up negative. After trying a few things, they couldnt get it to overheat at all to even a small extent for a while. He said when they finally "copy catted" the conditions where it overheated on me they got the temp to go up to about 3/4. Then they tested again, and only then did it come back positive for hydrocarbons. And they said they hooked up a hose to the reservoir and got about 5 lbs of pressure back. So they said its a headgasket, not completely shot, but that it has enough of a leak to do what it has been doing. They quoted me $1,900 + tax.
Because its a high mileage vehicle, I dont have much money into it at all, and I have a clean garage (finally), and a spare vehicle for the meantime, I am going to tackle it myself. $300 in parts and a 4 day weekend coming up.
This is kind of what I expected to find out, I didnt want it to be the case, but oh well, even after all this I will still be less than $1000 into the vehicle, including purchase price. So I am not gonna cry.
Thanks to everyone for their input!

Take the time to get the heads surfaced. 

And pressure tested.

[Pete112288]

Finally have everything on hand except for a few replacement studs for the exhaust manifold that broke. Will pick those up tomorrow and begin putting everything together. Taking it down to this point was the easy part. The clean up and gasket surface prep has been agonizing haha, but want to make sure to do it well. This is what I saw when I pulled the heads, and I dont think the picture does it justice.

[jackelope]

Have the heads pressure tested while it's apart so your work is not all for naught....

Or don't.

[Pete112288]

Update...
So got everything put back together and fired it up today.
I took my time and had nearly a week off work to do so. Labeled everything and torqued everything to spec upon reassembly.
The only thing that I was not completely confident in was the injectors. The kit came with new basket filters and o-rings for them, so I replaced those. I had a heck of a time getting the old basket filters out though. One of them went into pieces but was pretty positive I got it all out fine.
It is idling horridly though. Very rough, almost sounds like a choo choo train chugging, RPMs bouncing between 600 and 1K. A lag when I give it gas before the RPMs go up. Is throwing a code for a misfire, the code was for "random" misfire, not cylinder specific. Plugs and wires are new. Double checked that the plugs are in correctly and seated well. Double, triple, and quadruple checked the wires and made sure the wires were in the correct order as well. Spritzed starting fluid around the intake wherever I could reach and nothing changed to indicate any vacuum leak. After running it for a while and starting it up a few different times, it wouldnt start. Would turn over but not start.
I am leaning towards the idea that I may have messed something up with the injectors. Thought about just replacing all of them, they arent too expensive or hard to get to, just have to pop off the upper part of the intake.
Anything I really should check that I havent already? Thoughts?
I also have a code for the MAP sensor. Could the two things be related or should I be looking for another issue there?
Thanks again everyone!

[Crunchy]

That sensor could be causing the problem.  Had one go bad years ago and the rig ran like i had 2 dead cylinders.