Jaguar_MBA

Folks, after the car has warmed up a bit and I am driving it a little harder, I push the car in 2nd gear to ~8000 RPMs but when the RPMs are climbing from say 2500 I get some weird power surges, as if the car is stalling out at ~ 5000 RPMS then when it hit s5250 RPMS the entire engine like cuts out and the RPMS fall to 4000 is RPMs...even if I keep the gas pedal at the same level of fuel delivery. Next I would shift to 3rd gear and exact same situation. So what could be causing the Engine to just cut out at 5250 RPMS...car has plenty of oil, No CEL is every thrown, running 93 octane, have N flash, and mazda put in the "hotter" new designed plugs.

The engine makes no noise when this happens it just cuts out and drops the RPMS way down. This is kind of dangerous I think, to just have the RPMS drop down .

Any thoughts as to what it could be. After I get some ideas from you all, I will go to the dealer and have them look at it.....once again it DOES NOT throw any CELs when this happens.

bxb40

I have the AT model, but on your engine, the secondary ports might open at that RPM. If it fails, the air to fuel ratio is messed-up, hence the drop in power.
I would take it to the dealer to check on those ports working properly.

MI_FamilyMan

Definitely not normal... I would get it checked out immediately. I won't even take a guess at what it might be, but obviously it is not something the ECU is picking up on if you aren't getting CELs.

Go48

This statement suggests that you are experiencing this when the engine is not FULLY warmed up. If that's the case, I believe that there is a fail-safe situation whereby the PCM will limit the engine revs if the engine is not FULLY warmed up. If you are experiencing this problem with the engine fully warmed up, take it to a dealer and have them diagnose the problem. It ain't normal.

Jaguar_MBA

Hi Go48...the car is normally fully warmed up and happens after I have been driving the car harder for ~ 30 minutes.

Petrus

Definately sounds like it has something to do with the secondary port opening/sealing... It´s about that rpm the 2nd port should open, and if it fails to do so you might experiencing something like you described. My suggestion is to take it to your dealer at once and have them take a look at it.

Jaguar_MBA

Rotarygod shared the following in a seperate thread:

"The primary ports only are open up to 3750 rpm. At 3750 the secondaries come in until 6250 rpm. At 6250 rpm the aux ports open. At 7250 rpm the VDI valve opens as well as a different intake pipe into the air filter housing."

Thus it would appear that my secondary ports are open already(3750 RPMs) even though I am having the power drop off at 5,250RPMS after driving the car hard for at least 30 minutes before hand.

On the way to church when I started the car up I was able to drive the RPMs right up to ~8000k with no issues in second to third gear shift. Engine felt smooth and with no issues. but the car had only been running for ~ 5 mintues prior.

MintyFresh

try a higher octane fuel - with mine it made a deal of difference

fray

iTrader: (1)

This happened to my RX-8. Was doing it for about a week before the CEL finally came on.

Have the dealership check your catalytic converter. Once it starts to go bad, it can block things up and cause lots of power problems (at least in my case) starting about about 4500 RPM.

At first I thought it had something to do w/ the secondary port.. but nope.. it was the cat. (Also if your engine has _EVER_ flooded.. chances are it's the cat.)

Jaguar_MBA

Fray, interesting thought on that...I have never flooded it before but have had a few harder starters....that could be it.

MintyFresh, yup I put in 93 octane.....and I checked to make sure my wife had not refilled it with a lower octane.

How is this for a scenario: My car has the "hotter" grade plug in the engine. When the car has been running for over 30 minutes or so, they get to hot and can not dissipate the heat and cause some pre-detonation. but I would think that any pre-detonation would cause a CEL...?

zoom44

could be bad coils.

Jaguar_MBA

Status Update... I have been driving my car for the last week or so and this issue has never re-appeared. I have taken it up to Redline multiple times after driving some long distance and no hesitation at all.

Based on some other threads I think I figured out the issue. First, I had the DSC disabled (10 sec hold down on the switch). Second, I was merging onto the highway from a short on ramp and spun the tires and kicked the rear end out some.......right after I did this I hit it into a lower gear and pushed the engine for some fast acceleration...the engine did find until it stumbled at ~5000 RPMs and cut out at 5,250 RPMS. I think the ECU dropped the engine into limp mode with the excess wheel spin from the turn/skid/merge.

I have the N flash and some people have been talking about the LIMP Mode for engine preservation.....any technical details somebody wants to share about Limp Mode. I did not see anything in my Owner's manual.