[silicon212]

Originally Posted by stucknok

My 1987 Caprice has no power on the highway and struggles to get above 60 mph. Normal driving in town everything seems OK. Once it gets on the highway and in OD, power seems non-existant. Car also doesn't seem to downshift correctly. I have to slam the gas pedal to the floor before it will downshift a gear. This car has the 305 "H" code engine. I have had it several places and received different diagnosis at each place. One said the timeing chain had slipped. One said I got a tank of bad gas, even though I told him it has been going on for 6 months. Any suggestions? Thanks in advance.

Does it produce a lot of heat while you're at speed? Almost, if not, on the verge of overheating? Do you ever smell a rotten egg or lit match (sulfur) smell? The power loss at speed is a big symptom of an exhaust restriction, usually a plugged catalytic converter. It could also be a timing issue (spark knock, ESC) or fuel delivery issue (carburetor, plugged air/fuel filter). My early money is on either the air filter or the cat. If your Service Eng. Soon light is lit, then by all means change the air filter.