Hello,

I bought a 2004 rx8 about nine months ago. I love the car but have had nothing but problems with it. The car now has 107,000 miles. I bought an engine from Mazda about 10,000 miles ago to replace mine with low compression.

Ever since I replaced the engine it has been stalling at idle and has a hiccup at about 4500 rpm's. I have changed MAF, Neutral switch, front O2 sensor, plugs, coils. After running out of ideas myself I brought it into Mazda. The looked at it and couldn't find anything. Told me I must have hooked the injectors up wrong because it is reading very rich. After tearing it down and charging me 400 bucks the told me they were hooked up correctly and have no idea what is wrong with it.

I have put about 10,000 miles on it like this but it is very annoying and my daily driver. I really need some help to solve this problem!

Thanks guys.

 

Are you getting any CEL error codes? Did you reset the KAM and NVRAM after you installed the engine? Are you sure you have all hoses and wires connected properly?
Verify your plugs, coils AND wires are in good health.

EDIT: found this with google search in about 20 sec... https://www.rx8club.com/series-i-tro...g-down-213277/

 

Typical dealer monkeys. Stalling at idle is generally due to a vacuum leak. There are many ways to diagnose this issue. That said, it could be a simple pin hole vacuum leak or it could be a loss of compression. It's not likely compression since the engine only has 10,000 miles but Mazda remans have been known to die that quick. It is rare though.

 

Yea I get a P0037 which is the back O2 sensor, I pulled the cat off, it is gutted. I also get p0470 code I believe. It's the secondary air pump code. The coils are about a week and a half old. The plugs I replaced when the engine was replaced. So Plugs and wires may be bad. I don't know how that would make it run rich. Oh forgot to say at idle it drops to about 500 then jumps up to 1500 or so. if it doesn't just stall right away.

 

Ya, I told them to check for vacuum leak first. After telling me everything they did. I asked if they did the vacuum check. They said they did, I don't know if they actually did. My next step is to go get the compression checked and computer flashed. I figured I'd get any of your opinions first, before I fork out unnecessary money.

 

Well the vacuum line to the air pump actuator could be leaking or the actuator itself could be bad. The gutted cat would not cause stalling at idle.

 

I didn't think the cat would make it stall, Well I guess I'm going to just take my car in and get a compression check, vacuum check, and get the computer flashed. I have no clue what else to do.

 

I have O2 sensors if you truly need to buy one to fix that issue, but I doubt it.

 

It's not the O2 sensors, they are not in play in closed loop (idle).

Engine; symptom troubleshooting.

M A Z D A

 

Still haven't found the problem. I am now changing the radiator that blew up on me in traffic. But, I was thinking if I bought a Cobb Access-port tuner, would I be able to adjust the fuel to air ratio since Mazda said it is running 100% rich. Or is that just dumb.