95 4.3 problems

[old Rusty C10]

truck is a 95 S 10 blazer with a 4.3 Vortec motor automatic. My son in law bought this with like 133K on it. It may have sat for a while prior to him buying it from one of the dealers that sells cars dontated to chairty.
Upon buying the truck we had to do some work to make it road worthy but for the price we paid for the truck, it wasnt too much.. I put a set of tires, upper control arm bushings, lower ball joints , wheel allignment, a trans fluid flush and a oil/filter change.

The truck had been overheating but we did notice that the coolant was low and it did leak some.. there is a hole in the radiator that has stopped itself up and the coolant is brown in color ( someone said that it appears someone mixed dex cool and green coolant i dont know)
The truck runs and drives ok but when we took it for the NY Emmisions test it ran at 2.50 HC which is the hydrocarbons and the NOx was off by .3
the limits were 1.6 on the HC i forget the limit for the NOx

He goes home and changes the spark plugs which were prolly from the shape of them the ones that came brand new with the truck, and he changes the ignition wires . He used Delco plugs as per the auto parts store and the mid grade wires from pep boys
We bring it back for inspection and it reads 1.80 HC
The mechainc i have been using for such things has gotten himself into kind of a pickle in the economy and he is losing alot of business.. and this mechanic tells me to leave the truck and he will run a diagnostic test in the AM.
Next day he tells me that the truck will never pass inspection and he cant do anything take the truck home.. He doesnt tell me what is wrong with it except its throwing oil... I figure hes full of it cause forst off he didnt charge me for the diagnostic and second HC means raw fuel not burning oil, and secondly when the plugs were pulled the diode was missing and there was just a little brown and grey ,like typical wear and the after junk left on the plugs by gasoline additives. They did not smell of gas and had no oil residue on them
Also since he has owned the truck he has put about 1000 miles on it including a trip to my upstate house and back.. since the hole in the radiator has plugged itself up it has not lost any coolant and it does not overheat. There is no coolant smell out the exhaust and its not lost any oil nor has the oil gotten that funky water in oil coffee with milk color

there is no dash lights on and we are kinda at a loss... I was thinking perhaps that because the old plugs were so old and because the truck sat a while ( i heard that this lot had tax problems and the vehicles sat about a year)the gas may have deteriorated some and the cat may be partially screwed up..
Can anyone give me any ideas? Meanwhile tomorrow im going to see if i can get the son in law here to have the radiator and all flushed and maybe plug the hole or something...
Money is a tad short here and also we need to get this truck past inspection as the state time is up and he can start getting tickets..