he has a chevy silverado its a beast but the thing is that i was driving it and turned on the a/c and about a min later i heard a ticking noise not thinkin anything of it i kept driving it and stopped at a bus stop and it shook pretty bad at idle then i keep driving a little further and the CEL came on... it sounded like it almost stalled its a V8 1988 truck it has 144,000 miles on it lol... its a work truck so we use it pretty hard everything basically has been replaced except the engine new tranny, suspension, etc.. and ideas? my dad said the timing belt or bent valves or piston.?