My car has bout 35 k (2004 coupe) and wanted to see when I need to change the spark plugs. I don't take my car to stealership, and I haven't had one of their maintenance things done since my car had less than 10K, so no one has looked at the plugs yet.

Thanks

 

The OEM are laser platinum, so they live a long time. In theory, you could wait until 100K miles, but I changed mine at 60K just because I was bored one weekend. They still looked OK, but the car did seem to like the NGK Iridium IX I installed better.

 

Cool, thansk for the info. How did it like the NGK Iridium IX I installed better?

I don't know if it's just my imagination, but I just notice less pick up and go...

Maybe I should wash / clean my k&n air filter.

Also, has anyone experiance lessening of HP with plenum spacer ? (at lower rpms?)

Thanks again.

 

The idle was better and just overall better responsiveness with the NGK. But I doubt your plugs are causing the sluggishness. More likely you need to run a few bottles of fuel system cleaner through to scrub the valves and combustion chamber of carbon etc as the ECU will trim timing as knock is detected from carbon hotspots.

Just use a good cleaner that uses synthetic detergents and not a plain old fuel injector cleaner, you need to kill carbon, not just varnish. The best bang for the buck is the Prestone fuel system cleaner at Walmart ($4.95 bottle). Run 2 bottles of it in a tank and I bet you will notice a difference.

 

Cool, I'll get couple of Prestone fuel system cleaner.

So there should be no harm done this to my engine right?

Thanks so much for your advice man, very helpful.

 

What about techron fuel cleaner from chevron? Does that kill the carbon spots?

 

Try BG 44K, I think that the name. Best cleaner out there. You can get from ebay or find a local distributor.

 

True, the BG stuff is probably the strongest available. But I would only use it on a really neglected motor that has run only Arco or some other econogas with the lowest additive levels allowed by law. What he has is probably some minor buildup that could be knocked out with something a bit less harsh. I worry about seals etc with the BG as the stuff really is nuclear.

 

Yea, I'd go easy on the cleaner and only use it if you've been using cheap gas. You didn't mention if you've replaced air filter. I'd also suggest cleaning the MAF sensor with a spray made for that purpose (easy on the surrounding plastic and the sensor itself. Made a real big difference in my buddy's car with 50k on the odo.

 

I've been only usng 81 octane gas and have 32k miles. Do I then still need the cleaners?

My airfilter is the (K&N) aftermarket one (forgot the model, but the blue flat rectangular one.) I think I need to wash it soon as it has probably about 15k on it. Gotta find the instructions to clean it online...


Maybe I'll still get the two bottles of Prestone fuel system cleaner and see what happens. As I've said, I don't wanna cause any harm

 

Quick update, I put in 1 botle of prestone so far, and i do feel more pick-up.

I also used a bottle of fuel system cleaner in our other old car, and the pick up increase is even more.

Thanks again

 

81 octane???

 

woops, no no 91. typo :P

 

I changed mine at 75K and it was a noticable differance. I would wait until 60-70K before you change them. You are still in great shape.

-Sean

 

+1 . . . And I follow up with 1 bottle of RedLine fuel system cleaner every 2.5k miles.