I have an 89 car that idles fine but bogs down when accelerating. This only happens when I am driving at highway speeds or below. The first time it happened i checked the spark plugs they looked ok but I replaced them and the problem continues. It also bogs down when the engine is warming up, I think it has something to do with how the fuel mixture is mixed in with the air? I haven't been able to figure out what is causing this problem and would really like some advice.

A number of things can cause a car to struggle to accelerate, from problems with the fuel system and exhaust to issues with the air intake and ignition. The easiest way to diagnose and fix a car that bogs down when accelerating is to take it to a mechanic and have them examine it.

One possible reason for your car bogging down when accelerating is that there is an issue with the fuel system. This could mean that the fuel injectors are dirty and need to be cleaned or that there is a clog in the fuel line that is restricting gas flow. It could also be a problem with the mass airflow sensor, which is responsible for sending signals to the engine control unit about how much air is entering the car's combustion chambers.

Another possibility is that the spark plugs are dirty or worn out, which can prevent them from firing properly and igniting the fuel to power the car. If this is the case, they will need to be cleaned or replaced. It's important to keep in mind that the spark plugs play a crucial role in your engine's ability to run smoothly, so it's a good idea to get this issue taken care of as soon as possible.