My 85 has started idling rough at cold start staying around 400-500 rpm then dying if I don't give it gas. After 10-15 sec warmup the idle and startup is normal. This started after replacing the radiator, which developed a leak at the outlet. Ran hot once with just rinse water in the cooling system with the old radiator after a flush. Any suggestions on what I should check out? I'm planning to look at the plugs and check compression to start out.

 

I did a compression check this morning, not too good, not too good:

#4- 100
#3- 115
#2- 115
#1- 115

I put some oil in cyl #4 and the psi went up. I also noticed a vacuum air leak at injector #4, no external fuel leakage I can see, but I hear air getting sucked in at the grommet on the connector. I'm wondering if silicone could hold up there until I can get new seals. I screwed in the idle adjust in and it seemed responsive and killed the engine. Battery reads 12.2V.