Power Drops @ 7-8K
 

After the latest ECU update I have noticed a new and disturbing power loss under certain acceleration.

To set the scenario, here is exactly how I have experienced and can consistently reproduce the issue:

At speed in 4th or 5th gear (approximately 60MPH)
Downshift to 3rd and accelerate at full throttle
Power comes on smoothly through the 6-7K RPM range
Somewhere after 7K a series of what feels like loss of fuel "bumps" or erratic "burbles" where the acceleration slows and drops off dramatically
Once past 8K the smoothness returns and comes on for the last 1K

Anyone else experience this sort of thing?

Note: I did not hear any detonation or strange sounds...but it is so obvious that the first time I felt while romping along with stereo UP and windows DOWN - immediately prompting the closed windows and close listening!

Thoughts?

same here. did you mod/replace your intake?

how about your spark plugs?? have you had a tune up lately?? could be a misfire.

1400 miles = needs a tune up? :|

no mods to the intake at this time - all stock

We need a Poll on this issue.

It would be nice to see if this happens right away or after a few miles?

Also if a PCM reset makes the problem go away for a while?

This is not the first time this problem has been noticed.

It certainly will not be the last..:(

I had a hesitation at 7-9k. Just felt kind of flat. Then it started throwing CELs. Turned out to be bad coils. I had them replaced last week (warranty) and now its running good as/better than new.

I noticed the same problem and I hvae the canzoomer 1.1

I have canzoomer 1.1 and RE intake with M flash.
feels stronger after 7 K .
in fact, i was out tonight in those rpm range and noticed how nice it was.

Guys,
I have the cz1.1, the L flash and rb catback. I think I was kind of spoiled with the Pre L flash's in which you could "feel the kick" at about 6-7k. There is more under the curve power now but I also agree that at about 7500 or so the power either flattens out or maybe actually drops just a little. Think maybe I have some bad coils? Engine is smooth otherwise. There is a differance with the dsc off but only a little. I had the L flash and added the catback and cz at the same time.
olddragger

I don't have a CZ and I doubt my issue was related to my "M" flash update. More the reason they applied the "M" in the first place. The defect in the coils was only apparent at high revs. Otherwise the motor ran great. If it hadn't thrown the CEL I probably would not have taken it in. It felt dead opposite of when the car was new. Fast accell to 7k then went flat, almost dragging to redline. Now with "M" and new coils the powerband is pretty even all the way up. The mechanic was able to diagnose the problem through visual inspection of the coils. I found another thread with pics that shows this pretty clearly.

https://www.rx8club.com/showthread.p...highlight=coil

haven't noticed this in my car yet. have not reset the pcm.

I had somethin similar happen to me when car engine was still cold.... but rather at around 5k rpm... in 1st.... then shifted to second and again at 5k... I felt a flat spot... not sure what to make of it :(

just got my M flash.. and don't notice that problem with my CZ on or off. I did just get new plugs when getting my flash too..

I will keep an eye out for it.. but I have been running the car hard to heat it up so I can get under the exhaust to track down a rattle.. So I think I would have noticed since I've been listening and driving hard.

I think that RX8friend said that M flash does some wierd stuff above 7k RPM's tho..

I have the M flash and the RX8Store exhaust. My 8 has a very noticable power drop at 6K when downshifting and accelerating. The power drops for about 400 rpm then is kicks back on.

My CZ1 is on it's way so I'll see if that gets rid of the power loss.

This might explain your problem.

Page 5-4 of the Manual (US Version) in the Note box:

"To protect the engine, when the engine coolant tempurature is low, the engine does not run at high speeds. The fuel supply will be cut at an rpm lower than the red zone."

I've noticed similar behavior a couple of times when accelerating in 4th: at about 6500-7000 rpm, the engine starts making "knocking" noises and starts losing power. Mazda has evidently noticed it, too. A new PCM reflash called "MSP04" addresses this problem. It was released on 6-2-04, and describes this problem almost exactly. This bulletin is listed on the Rosenthal Mazda website:

http://www.finishlineperformance.co.../01-022-04.html

(The site home is: http://www.finishlineperformance.com/rx8/index.html)

Three weeks ago, I took my car in to get this problem diagnosed because it was starting to worry me. The mechanic drove my car 25 miles and couldn't duplicate the problem. Afterwards, he flashed the PCM with the new MSP04 as part of the dealership's standard procedure to perform the latest reflashes and recalls when a customer brings a car in for service. When I picked up the car, the advisor said, " Our tech couldn't isolate the problem," so I drove home thinking the problem might still be there. When I got home, I researched the MSP04 they had performed, and realized they had fixed the problem without even knowing it! Anyway, my 8 is running fine now, the problem has not reappeared, and I've even detected a bit more mid-range torque.

You know, on most cars that either have a cam shift or secondary intake kick in at high rpm, you get this satisfying rush of power. I think I was on K and now on L, and in both cases, you can feel the secondary ports open around 7k and you get a little more power, but it isnt that great, and fairly uneven. I blame it on emissions tuning. But it is my primary disappointment with the engine.

I agree with the power drop. I had the M flash two days ago. Before the reflash I had a noticeable bump at the 6250rpm intake opening....now it is just smooth power until I hit 6500-7000, and it simply goes flat....then comes back in at about 7500-8000....I am very disappointed. Also, if someone has really bad gas mileage, let me know!!! I am averaging 12-13 mpg. HELP!