Maybe just a tune-up?
 

I have a 98 4door, 5spd, 4cyl. She's got 255,000 miles and its starting to run a little rough. This weekend, I am going to replace the cat. converter b/c it's rattling and is really annoying. I am noticing an issue when accelerating. after about 4,000 rpm, my compression drops bad.

I am wanting to do a general tune-up (new spark plugs, wires, tranny fluid oil maybe a new fuel & air filters) Do you think this will help with the loss of power?

Thanks for any feed back!

Kurt

Does the check engine light turn on while driving? Have you checked for error codes?

Have you done a compression test on the engine?

A tuneup is a good idea. Use the NGK plugs recommended in the owner's manual. There is no external fuel filter that I am aware of on a 98. Air filter is a good idea. The distributor cap and rotor are probably more important the the spark plug wires.

The check engine light was coming on then going off. I ran the numbers and it was for the cat.

Every once in a while, the car will turn off at highway speeds and then start back up...

Fortunately, I have a family mechanic at the Honda dealership (my dad was a salesman there for 20+ years) I'l hand it over to him and have him fix the stuff, I'm just wondering what I should pick up at the auto parts store for the tune-up before droping off the car tomorrow.

I would pick up the spark plugs and the air filter at a parts store.

Distributor cap and rotor from the Honda dealership. You can get these at the parts store, but I think Honda makes better ignition system parts. May pay $15 dollars more for them, but probably worth it.