I just got ahold of an '89 Mighty Max with 54,000 original miles. Did a full tune up, with the exception of a fuel filter and a timing belt. The truck idles fine when i first start it but as soon as i tap the gas, it bogs down and acts like it's going to stall. I was wondering if anyone knew a solution to the problem other than raising the idle? I have considered a vacuum advance, but I want some tips before i start pulling things apart, as I'm new to these trucks.