I recently purchased a 2004 RX8 with 91k and 62 mi on a rebuilt engine from Rotary Resurection the car sat for four years before I bought it. I have been chasing CELs since I got it. It would stall when it warmed up but idled fine when cold. I bought a BHR midpipe and Bennett built Ls2 coils with new MSD wires and new iridium plugs. Last week it threw a p0171 and died on me. I found a nipple that had failed on the UIM. I recapped it and thought I had my issues behind me. I replaced the fuel pump as a precaution to eliminate that 30 min stalling issue. Today I drove thirty miles to work and was felling good about the car. It ran great. I did the 500mile oil change and drove home. On the drive home I started getting a flashing CEL that would go away and return and the car began to bog down and lose power. The OBD scanner said it was a p0301 misfire. I tried to drive a couple miles to the next exit and the car died. After I had pulled over I noticed that the coolant was leaking out and there were spray indications around the rad cap and overflow tube. I got the car towed home refilled the reservoir and now it won't start. When the motor quit I had my foot on the gas as a habit. Did I flood it? What next? Thanks, Pat

 

If it's flooded, try deflooding it. Gas pedal all the way down, crank for 5 seconds, stop and wait 30 seconds, gas pedal down and crank for another 5 seconds, wait another 30, then try to start normally. If that yields no result, I'd pull the leading plugs and see what they tell you. If it's flooded, they'll be wet with gas.

 

It sounds like plugs will be wet with coolant.

 

The plugs are clean and the font leading plug was half black half brown all others were normal. My p0301 code was showing a misfire cylinder #1 No fuel and no coolant on the plugs. That to me is pointing to a bad wire, coil or Harness the wires plugs and coils are new but I don't know. Maybe the coolant failure caused the engine that has little compression to heat up enough that it quit before it did damage The car will stall when hot when putting on the brakes or putting it in drive. it is now about 530 miles into the break in so I know it has compression issues. . Thanks guys. Pat

 

In your first post you said it would stall when it warmed up.
Along with the other issues you were having, I'd guess it was already failing.
Could be the previous owner didn't follow the break in procedures when he got it back.

Or he could've been a total d-bag and swapped the rebuilt engine with a bad one before selling it.

 

What MAF sensor are you running in the car?

 

It says Toyota Nippon Denso on it I have cleaned it a number of times. In fact I don't know if it's related but cleaning it with MAF sensor cleaner was one of the first things I did. The screw that is more inboard to the throttle body engages the first few threads and then spins. Which may be a factor. The car now won't start and whines a bit and you can hear a fan. It used to start the first or second try when cold. If it was hot you have to wait an hour or two. Does that maybe mean it's flooded. After 3 attempts I quit because I Had to go work Any ideas? Thanks, How do I know if the motor is shot. It says right in the break in instructions that it will run poorly due to low compression Till it has 1000-1500 miles. I need to find the source of the coolant leak too but if the motor is blown I really don't want to waste a whole lot more effort. Thanks, Pat

 

The only way you're going to know if the motor is shot is with a compression test. The signs point to low compression, but even a rebuilt car shouldn't need an hour or two to cool down before starting hot. So get it tested so you know what you're working with.

It could be as simple as some bad vacuum routing too. If you can get it running again, I'd suggest hooking up and OBD reader and seeing what fuel trims and airflow numbers you're seeing at idle or otherwise.

Is there any other information that may be relevant? Is the car, especially the intake, stock?

 

The intake is stock. I think it has the VFAD removed. It has the stock air box for sure. Other than that the only thing I've done to it is ignition, plugs, wires midpipe

 

If you stripped the MAF screw it could be an issue.
I stripped mine once.
I fixed it by putting some JB weld in the hole, letting it dry and redrilling it.
They strip out easily.

 

About that... I actually have stripped MAF threads, although it's not messing up my car.

From what I have read, you can wait for the weld to set, and screw in the screw, unscrew it, then wait until it cures. Is that true? The guy at the store insisted that I should wait until it cures, then tap it with a tapping tool, then screw in the screw. Is that necessary?

 

I think the most correct way is to plastic weld it which is why I didn't fix it yet I think you could get away with the next size screw up or the method you just described by letting it harden and tapping it. I have not had success just gluing stuff like that in. Pat

 

They're so small I don't think tapping is necessary, and Idk what size it would be.
I don't remember if I used the original screw or one I had handy.
You don't need to tighten them real tight, just snug enough to seal the O-ring.
Did mine a couple of years ago, no issues.

 

Gorilla glue gel, let it set a few minutes and it will get really thick, then install the screws, works like a champ.