Help!! Pinging, Loss of pwr, Rough idle w/ Slight Shaking I just traded in a base model 04 rx-8 for a 04 Grand Touring.(both automatics)
I think I made a big mistake because the base model never gave me a problem.

Anyway, I have a 100k 8yr warranty on the Grand Touring so the dealer has been taking care of every issue. This is the sixth time I have dropped it off in two weeks. It has been running rough at idle. It idles around 1000 and drops down to 800 or so and then you feel the car shake. When you put it in drive or reverse it stops because you have a load on the engine, and if you ease your foot off the brake a little it will jump (like when you let the clutch out on a manual w/out enough power) because of this rough idling problem. ITS DRIVING ME CRAZY!!! Even more so because the base model purred like a kitten for 2 years. It has also started pinging ever so little at higher RPM'S and seems to lose power or not have as much pep as my old one.

The dealer changed the plugs, updated the computer, did their so called 120 point inspection. I will be bringing them the posts from this site tomorrow to help out if I can. They say some of these automatics tend to run rough. That is a line of crap on my part. thanks for any input!!

 

Check your motor mounts and flash.
The 04 auto's (mine included) have an issue with the motor mounts. It
seem wosre while in reverse with the brake on (cold weather enhances it too).
I have an R-Flash, there might be a later one (do a search on this site).

 

Mine idles at 800 as well but it's smooth and the car doesn't shake. Mine is the 6 speed manual though.
I'd say, your idle speed is perfectly normal. For the roughness and shaking in idle, let them check out the motor mounts - apparently there were quite a few people who had a problem of similar nature and the culprit was a busted mount.

Pinging: I have no idea. Do you use premium gas?

 

they should be calling the tech line and the tech line should be telling them to take your PCM out and send it to Mazda for reprogramming.

 

What kind of mileage does the new car have and did you contact the previous owner?

 

Care to do a compression test yourself?

 

Vacuum test may suffice. The car should have a good 15" @ idle.