have a 04 with 65,000 miles on it just changed plugs, wires and coils but still doing the same thing when it warms up idles rough and stalls every so often does not do it at every light just a couple of times a day then will run good for 3 or 4 days then do it again. The engine light does not stay on took it to dealer and they could not find anything wrong with it. Also took car out late the other night just to see how it would run out got to about 105 and took it a couple of miles to get up to 115 then seemed like it would not go any more. Also noticed that the rev limit light did not come on. Called my dealer back this morning to see about a compression test on engine and they had theres stolen and have not replaced it yet. Been reading thru threads wondering if i need to change the cat converter out.

Any advise would be appreciated

 

You can check the compression.

If you are mechanical... open the hood and look for vaccum leaks.

Do you have an after market intake?

Fuel pump filter? Try a gas additive.

 

do not have aftermarket intake.

I have not changed the fuel filter on the car will pick one up on the way home. Checked for leaks over the holidays could not find one.

 

Mag: I was getting this from my 8 last month. Being an 04, I had oil blow back build up in my intake on the throttle body and down in the lower SSV valve. I had a buddy from this club figure all of this out for me. But I'd look at your intake and throttle body if it is still doing this.

Here is the full thread.
https://www.rx8club.com/series-i-trouble-shooting-95/rpm-dropping-%3D-engine-stalling-162200/

But because it only does it some of the time, I'm not really sure.

 

vacuum leaks if they are present would constantly cause problems, not cause intermittent problems. with a vacuum leak you will hear a whistling from the leak as air is escaping from the break or missing line. it will also cause an erratic, rough, or flat out stalling if the leak is large..

at any rate, have someone rev the engine a little in neutral while you stan at the rear of the vehicle and hold a towel by a muffler tip. when the friend reve the engine, the towel should move cinsiderably indicating the exhaust gases are flowing freely and there is no obstructions..which will happen if a converter is melting, plugging or has broken apart, clogging the exhaust system. check teh air filter for a restriction as well as look into replacing the fuel filter. feel free to have the compression checked for good measure. if the problem is intermittent, i could be caused by a loose afm wire or faulty dsc component which will cut the throttle if it sees slippage. you might want to test the components in the drive by wire setup. make sure the throttle body is not gummed up..but since its intermittent, i would feel it best to say that it may be an electrical malfunction...

 

To change the fuel filter, you have buy an entire fuel pump assy. They are a complete unit, not cheap I mind you.

 

Check out the new engine club...sounds to me like you'll be joining it

 

^^^thats true on the pump/filter assembly, its all one unit and its not cheap. perhaps doing a fuel pressure test will yeild better results. i wouldnt find it likely that the filter would be clogged but when you're having sporadic problems, things need to be checked for good measure to rule out possible causes.

 

really,

at ~ 130 bucks for a complete fuel pump i think that is pretty reasonable..

beers

 

you know, that really is a reasonable price..especially considering a lot of parts for the 8 are sky high in price

 

^ ha yeah a fuel pump assembly is only 50 bucks more than 4 spark plugs so i say that's a great deal haha!

 

just as a heads up, you can buy the oem NGK plugs from napa or advance auto for only $20 each...