I need some help and am turning to this forum for it. I have a 96 GMC K1500 that had a new engine about 3,000 miles ago. The engine has a warranty, but not on the labor so I need to figure out the problem to see if it is covered. It stumbles at low RPM/idle and seems to clear up with higher rpm. Check engine light will flash and go off-no hard codes. Here is what I have changed: -Cap and rotor (not the cheap ones) -plug wires -coil -Upgraded the spider injectors to the new style -fuel pressure regulator Fuel pressure is reading 60psi. I had a friend hook up a tech 2 to look at misfire data. It showed cyl#3 misfiring ALOT! It also seems to be using coolant but is not going into the crankcase. Pulled the spark plugs and did a compression test which all showed good numbers (135-150). #1 plug was all crusty and I figured this was where my antifreeze was going. What had me puzzled is that it was #3 that was misfiring. I pulled the lower intake and I could see where antifreeze had been getting into cylinders 1 and 3. (See first pic). I'm puzzled as to where this antifreeze was coming from since the rubber around the coolant port on the gasket appeared fine. Needless to say, I replaced the gaskets with the new metal ones and put it back together. Still has a miss with flashing CEL!!! I don't know where to go from here and was hoping someone else may have some pointers.