Possible heater core trouble ?

[cmr29sun]

94 4x4 Had anti freeze smell inside truck, now and then the gurgling sound as I read posted somewhere thats the sound of air where it shouldn't be. Next thing was I would get back in after a ride and had the film on inside of windshield. I took all this to be the heater core about to let loose. I didn't get any leaking on the inside of truck though. I had leaking from under starter area. All I could tell was it was from above and dripping off everything on the way down. We bypassed the core by just connecting the two hoses that were connected to it. System definitely needs a flush by the looks of all the crud we saw in the hoses. Can't smell anti freeze anymore and it seemed the leak stopped except there was a small amount of leaking when we parked on a hill. Hoping that was just stuff from earlier leak and so far that's all we've seen.The check engine light is now coming on and off when driving. It seems to run fine(or as well as it did) then the next time we drive it it's just not right and doesn't have the same pick up (a little sluggish). Were we wrong to assume it was the core ? Is it ok to bypass it the way we did ? Was there something else we needed to unplug and didn't causing the check engine light now to come on ? If it matters the heat or AC hadn't been run in at least 2 years due to electrical problems we had a while back. Plus not much need for it here in So. Cali. Thanks for any info
Cmr29sun

[MT-2500]

As long as you did not plug the hoses.
A bypass is OK.
Did you get it filled up good with coolant?
Your engine light or engine running is from a different problem.
If check engine light is on you need to get it on a engine scanner and get codes and see what is going on.
Is the light on steady or blinking?
Post back code no.