Dear Doctor: I just bought a 1983 Ford Ranger with the V-6 and four-speed manual transmission. I did a tune-up on it, including new air filter and belts. It’s now backfiring and spitting and sputtering as it revs. When the weather is hot the truck stalls and takes a bit to restart. I do all the work myself and don’t want to spend 300 bucks on a new carb. Can you help? Adam
Dear Adam: The first issue to determine is whether the tune-up created the problem. If it happened after you replaced the tune-up parts then you could have a spark plug wire crossed. If the firing order is correct, then the next step is to check the carburetor to make sure fuel is not leaking from it. The EGR valve also has to be checked to make sure it is closed all the way. A compression test may also be required. If the truck is equipped with a distributor cap, then it also needs to be checked for cracking.