87 e-150 302

Hello everyone

I was reading the post about top speed, and someone suggested to check the throttle linkage. I don't think my top speed is bad, but my gas pedal has been really hard ever since I owned this van. I was wondering if this can affect the performance of the van. To get a smooth gas pedal, do I just need to change the cables? What are the usual problems related to a bad throtle linkage?

Thanks