I have a problem with my 2000 Galant GDI. When idling or driving the cars acceleration power goes up and down erratically on its own. This is not a consistent problem but is getting much worse. This shows in the revs, changing from between 500 and 3000. It feels very jerky and is starting to really annoy me. I am taking it back to the dealership today as it has a warranty for repair but I would really appreciate anyone’s thoughts on this, thanks.

Guys said they think its the fuel filter. From looking through other postings this could be right, fingers crossed.

Had an Audi once which did that, and my first suspicion was electrical. Took it to my mechanic. Surprisingly, the reason was because of the accelerator cable, which he re-adjusted, and never happened again. How it happened, why it never happened before, no idea, but it fixed it.

If the idle goes down too, possibly some vacuum hose leak in the engine compartment.

Else, good mechanics these days have hand-held diagnostics computers which may be able to find a fault with your car (even if it's a GDI).

Thanks for that, will pass the info on and see if it helps any :)