fxdsconv2000

I have been searching the forum for the power loss problems and so far I can't find anything that describes the problem I'm having so, I'm looking for ideas.

Here is the problem:
After driving long distances on the highway with the cruise control set at 80 mph my car losses power. The power loss is to the point that even at WOT I can not maintain 80 going up a small hill. As I go up hills my speed decreases to about 74 then as I crest the cruise control continues to increase speed until I reach about 88-90. At that point I turn off the cruise and maintain the speed manualy. Then as I get off the highway first gear (from a dead stop) feels like 2nd or 3rd gear and exhaust note is louder and kind of tinny.

Also with all of this there has never been a CEL and the dealership can't find anything wrong. They can not reproduce the problem.

I was thinking something is getting stuck open but, accourding to the post I've been reading a port being stuck open with produce a CEL.

Any ideas?

expo1

Clogged CAT ??

fxdsconv2000

If the CAT was clogged, would the power come back? Because the power does come back (forgot to mention that in the original post).

expo1

https://www.rx8club.com/series-i-tech-garage-22/choking-high-rpms-61834/ is one thread I found. Doing a search for ' clogged+cat" will bring back more. It easy to check, just unbolt it and look inside. But I was just making a guess.

Sea Ray

Has your car been flooded before? More than once?

A cat will burn all the excess fuel inside and destroy itself and the loose pieces can clogg/restrict exhaust flow.

But the fact it takes time to bogg down is weird.

zoom44

you have 2 problems-

1 power loss- could be caused by an overtemp situation. but i have never had my CC lose more tham 1mph in big mountains. so there is definetly either a heat issue, a spark issue or a cat issue.

2. cant reproduce the problem- techs are not allowed to drive over the speed limit to verify a problem. so how do they verify yours?

lurch519

i read an issue that someone on here had that what was happening where one of the intake runners was sticking open or closed when the engine got up to temperature.

fxdsconv2000

Thanks for the replies. I don't think it is an overtemp problem. It happens at 80mph with the outside temp at 20 degrees.
The problem is the techs are telling me if they can't reproduce the problem there is nothing they can do about it. It happens at 75mph also it just seems to take longer.

Correct me if I'm wrong but aren't there ports that open right around 4,000 rpm? If so if those stuck open wouldn't it cause a similar problem?

As far as flooding, nope never.

Lurch,
I remember reading something like that before (long time ago).

fxdsconv2000

One other thing. It seems like it is just in the lower rpm range (below 5000) that the problem happens.

lurch519

i had a similar clogged cat problem, but it wasnt that noticable to me. i could still chirp 3rd gear and this is what my cat looked like

https://www.rx8club.com/showpost.php...04&postcount=5

swoope

iTrader: (5)

i had this happen to me once. has not happened again.

https://www.rx8club.com/series-i-trouble-shooting-95/rx8-unable-grab-revs-5-6th-52522/

sound like yours?????

beers

fxdsconv2000

Yes that sounds almost exactly like my problem. I'll print this out and take it to my service guys.

Thanks

musclecarconvrt

Great. Mine did the exactly same thing about three weeks ago. My 8 has about 44k miles on it. It was about 27 degrees out and I had been on criuse control at 75 for about 15 minutes. I assumed something had just frozen up because it seemed to corect itself after I shut it off and restarted after letting it sit a while. Hasn't happened again. No CEL yet. I sure hope it was just the cold in my case.

swoope

iTrader: (5)

well if it helps,

when it happened to me i took it to the dealer.. i have a good relationship with them...

the master tech changed the gas to preimum and it has not done it again. i also ran a can of b@g 44k through it.

been about 6k miles since the problem...

who knows!!!

beers

zoom44

recent info that suggests heat problems at sustained high rates of sped. granted this was in 100f temps and 90+mph but that was when it boiled over. the pcm will start chuckign timing(and power) long before then to help preserve the engine.

id forgotten about that previous thread where there was a intake track problem. im amazed i guessed that. that i didnt even consider it(an intake issue) after reading this thread is a wonder....

fxdsconv2000

Well I can verify that the issue does not happen if you drive a long distance at 30-40 MPH. I made a trip today that almost always causes the problem but, due to heavy snow I didn't get go over 50 mph for more than 20 min.

I printed out the other forum topics and took it to my dealer. The service writer completely agreed that that was the problem, however the tech doesn't want to do the work with out reproducing the problem.

Well I guess I'll try the other dealer in town.

swoope

iTrader: (5)

funny tonight i was changing the oil to royal purple and rotating the tires, when i got back from a short drive my car had a wistle to it.

this has happened one time before, right before i had the loss of power.

this should be interesting...

beers

Mr986

My wife has an '04' 6spd with about 22K on it. Had identical problems 3 different occassions in the past 2 months while driving on an interstate at 70-75mph in 6th gear.

Started up a slight incline and lost speed while on cruise. Stepped on the gas and nothing happened. Downshifted to 5th with some slight increase in speed. I will bring this up at the next oil change and would appreciate further posting s on this to confirm that it's a stuck secondary shutter valve.

fxdsconv2000

Right now my dealer won't do anything about it since they can reproduce the problem. I hope your luck is better than mine. As for me I'm taking my car to the other dealer in town to see if they will do anyting about it.

invasion08

iTrader: (7)

Do you have hear a knocking sound when you have this problem? When my car was warmed up i would lose power and sometimes hear spark knock. Brought it to the dealer when i was having the problem and had the service amnger verify it. Bring the car in when you are having the problem dont let it sit overnight get them to drive it with you in it when you have the problem. My apex seals went when the engine was warmed up and mazda gave me a new engine

musclecarconvrt

I have not heard any knock. I'm pretty sure the CPU would jump on that instantly. I got a flashing CEL a couple of weeks ago that went off after about 20-30 seconds. It didn't want to go past 7k rpm. Since then, I've been reving it out to 8500 in every gear all week and have not been able to duplicate the problem. I'm going to just wait and see if it becomes repeatable. Otherwise it would just be a waste of time.

Rob Lay

I'm getting similar symptoms on my club racing car...

https://www.rx8club.com/rx-8-racing-25/scca-t3-rx8-loss-power-83300/

Any final resolution? Cats?

fxdsconv2000

No resolution yet for me. The main problem is even if I drive it directly to the dealer the problem goes away as soon as I'm off the highway. I never let it sit overnight.

musclecarconvrt

I drive about an hour each way to work every day on the interstate, so I get lots of "test" time. After gas hit the $3 mark last summer I really began watching the rpm's. Shifting at 3K-3.5K and setting the cruise at 65 got me 23-24 mpg. It also fouled the heck out of my plugs and I think it taut the CPU to like it. The car just wasn't made for that. My problem has not re-cured since I went back driving car the way it was meant to be driven. Now I shift whenever I feel like it! Sometimes it's 5K, sometimes it's 6K, 7K, or 8k. More spirited and varied shifting seems to have blown the cobwebs out for me. 19 - 20 mpg is still better than the truck I traded for it anyway! So, I'm spending a few more bucks a month in gas and enjoying my car again!