Bought from orig. owner @ 58,000 & now has 78,000. He confirmed GM's mpg @ 17/25; now getting 10mpg. Care since 58k: plugs, wires & fluid changes. One-month ago a not so credible mech installed an EGR following his instruction to troubleshoot excessive fuel: Car began missing, making popping noise; failed to down-shift into passing gear. Alternator replaced last wk: Mech re-set timing and claimed the duel TBI's need pro-cleaning or replaced. Has new muffler & catalytic converter checks out good. Car still missing, popping & using far too much fuel.