My MM has lost a step - what can I do?

[Ozz]

Greetings,
My MM recently passed 100k miles and has seemed to have lost a bit of power and drivablilty. I don't have any engine codes so I don't know what to look for.
I guess it could just be regular 'wear and tear' but the change has come on fairly quickly. The engine doesn't seem to want to rev as easily as before and tends to surge and bog as it gains rpm's. The idle is just slightly rough on occasion.
I did my 100k service (PCV, Fuel Filter, has older iridium plugs, coolant, rear end grease, etc) so I don't think it's any of these things.
Are there any other 'usual suspects' that I should investigate?

Any suggestions would be appreciated.

THANKS!

[martyo]

Pull a plug or two and take a peek.

[whitey]

cop's probably, ive heard many of people...including myself that has had their cop's take a crap around 100,000 miles. mine never threw a code, so i could never diagnose it to a T, but musclemerc told me right away what it was, and sure enough, $115 later...:burnout:--whitey

[tbone]

Check out my "Cheap Cops" thread.:)

[Fosters]

cop's probably, ive heard many of people...including myself that has had their cop's take a crap around 100,000 miles. mine never threw a code, so i could never diagnose it to a T, but musclemerc told me right away what it was, and sure enough, $115 later...:burnout:--whitey

Yup.

I've even known of people who washed their engine, with a bad cop cover gasket, and needed 1-2 cops. :o

Damn things would only do it under load/acceleration, so buying one and swapping it into all cylinders to see which it fixes would have taken days to troubleshoot... so I had a diagnostic done to find the cyl numbers. I mean, I've known of people who have had to do that due to washing the engine... :o

[Timw286]

I would start cheap and run a few tankfuls of quality fuel w/ some STP fuel injector cleaner and take it from there

[Odinson]

Plugs, cops. Regular maintenance anyway.

[sd8683]

Yup.

I've even known of people who washed their engine, with a bad cop cover gasket, and needed 1-2 cops. :o

Damn things would only do it under load/acceleration, so buying one and swapping it into all cylinders to see which it fixes would have taken days to troubleshoot... so I had a diagnostic done to find the cyl numbers. I mean, I've known of people who have had to do that due to washing the engine... :o

Same here! Cop closest to the firewall on the drivers side, and the worst part it was my girlfriend that figured out! Because it wasn't having issues til a week or so after I washed it!

[Ozz]

Thanks for the replies. I was actually thinking COPS too.

I checked the plugs and they all looked normal. I did rinse the salt spray off the engine a few weeks back when the weather was warm. I think that's a pretty good place to start.

I don't think I've missed any regular maintenance so it's none of those things.

Thanks again!

[JOEMERC]

Also look into your cats. Maybe starting to clog up,maybe time to gut them out , lol

[WPG_Merc]

Also try some Sea foam in the tank & spray some in the spark plug chambers & throttle body,It did wonders for my MM.

I had the same prob before & found it was bad gas,Had to run it dry & gas up at a better station.:)

[Pat]

COPS, clean maf, fuel filter (should be changed every 15 K but people forget), check PVC's vacumn lines. There are other items but these can cause your problem.

[CBT]

Yup.

I've even known of people who washed their engine, with a bad cop cover gasket, and needed 1-2 cops. :o

Damn things would only do it under load/acceleration, so buying one and swapping it into all cylinders to see which it fixes would have taken days to troubleshoot... so I had a diagnostic done to find the cyl numbers. I mean, I've known of people who have had to do that due to washing the engine... :o

Save some time, Marauders have "true dual" exhaust. Stand behind the car and listen to which side of the exhaust is missing/popping/pinging and you can eliminate one side instantly for spark plugs or COP's. Unless you have had an X-pipe installed.

[Ozz]

CBT,
Don't we have an H-Pipe?

WPG_Merc,
Doesn't SeaFoam make the car smoke? I seem to remember that being the case.

I friend of mine who used to work at a (toyota) dealership told me that any time anyone brought in a car with rough idle or general drivability issues, they'd put a couple bottles of the Chevron fuel system cleaner in the tank and let it run for awhile and 80% of the time, the issue was solved. I've been using the Chevron stuff every 10k miles so I'm wondering if SeaFoam will do any better...

JOEMERC,
How hard is it to gut the cats? Do I need to split them and take the platinum(?) medium out and then rewelding them together or can it be done an easier way?

Thanks!