2004 loss of power and sputtering exhaust
 

Ok guys i have to admit im still very much learning about the technical side of my car so any help would be GREATLY appreciated.

I have a 2004 rx8 i am experiencing power loss i was going about 70mph around 4-5,ooo RPM and the engine slowly just started losing spower. Once i hit about 45 unable to gain any speed i got it towed back to my house.

I am able to start the car currently engine turns over no problems but when i rev the engine in nuetral the engine is strugging to rev up and you can feel the car rattling and i can hear the exhaust kind of sputtering, not back firing just..sputtering. After a few minutes of having the car on the RPM idles around 5-800 and feels like its about to die.

The fuel pump was changed about 6 months ago along with the filter, the gas tank was about half full and the oil levels were normal.

I rented a fiuel pump inspection kit to test fuel pressure but when i researched and youtubed how to check the fuel pressure on a rx8 i was abloe to find nothing. Any advice would be EXTREMELY appreciated.

How long on your ignition?

The neutral load sounds like it's having trouble firing correctly. The highway massive power loss sounds like a clogged cat, which comes from ignition health.

Thank youfor your input, how do you recommend i check to see if thats the problem?

Would it make sense or helpful to run some type of simple fuel cleaner through?

And what exactly do you mean by how long on my ignition? If you are reffering to how long it takes for the idle to drop really low and struggle its within a couple minutes.

Ignition = spark plugs, pug wires, coils. If these are over 25 to 30k miles they need to be changed. Your cat could be destroyed or clogged. There are a few different ways to diagnose a bad cat. First, do you here any weird noises (rattling) from under your seat (where the cat is)? Second, after driving the car hard (which I guess you can't do at this moment) look underneath and see if the cat glows. To accomplish this you need to be in a dark area with no lights. If cat glows then your cat is bad. Third, pull out the cat and look inside. If the material is broken your cat needs to be changed.

first thing to check is the ignition, there is a factory bulletin running around about how to check the coils, and or you can use a timing light. you can just replace the whole ignition system, but i like to make sure its not the problem first, up to you.

second thing would be the catalytic converter, unfortunately. easy thing might be to remove the rear O2 sensor and see if it gets better. if it does then you need to go cat shopping :/

if its none of these, then you should start at step one, check the engines compression, etc etc