I believe my car has a bad main relay (hard to start when warm) but it has also developed an issue of surging under part throttle while driving. Basically if you let off the throttle a bit and go to reapply it you have to almost fully open the throttle before the engine will cut back on. Under higher loads it runs smooth as silk and full throttle is not a problem but driving around town can be a jerky experience. The problem does not occur consisently.

Could this also be a symptom of a bad main relay?

 

that sounds like something that happened to me a few times I really don't think it's a relay check ur vaccum lines sounds like u have a huge vaccum leak that or ur map sensor took a ****. check the vaccum line going from the fuel regulator to the intake manifold that hose right there has caused that problem for me a few times just check all ur vaccum lines make sure they are all connected and seald properly an listen for leaks