Power Loss Issue
 

I'm a bit concerned that my 8 is suffering from low power output. I've noticed that it doesn't seem to pull as hard in the upper RPM (>5k) like it used to. I also raced a friend in his sentra se-r (2009, rated for 180hp/170ft-lb) and was quite pissed when he had no issue keeping right up with me from a dead stop, as well as a 2nd gear pull.

I searched the forum and found possible causes for this and it seemed most pointed to a failing catalytic converter. I dropped the cat an hour ago to inspect it for damage and it is 100% fine.

http://www.flickr.com/photos/markf5020/8721413148/
My other searching seems to be that it could be a compression/engine failure sign, which makes sense, however there are no other signs of these things. My economy is on par, no hard starts, my only incident of flooding occurred when I moved the car without letting it warm up properly in -20C weather, which seems totally understandable. My plugs and coils and wires were replaced in the fall so I know they are good.

Is there something I am missing here?

oil change if it needs one and check your air filter, tire pressure and tire condition. fuel situation? (octane u use)

idk where you are located but if its hot out powers going to be less

aso if this is based off a "race" did you turn off traction control, launch properly and shift properly? do you have bald tires?

with a good running car only reason for losing is driver error i embarass 328's and 330's

All the small things you mentioned are meticulously taken care of.

And yes I know how to drive, regardless of the dead-stop drag race, a 2nd gear pull requires no shifting or anything, just to merely put my foot down and the results were the same.

all that leaves of the "small things" is your fuel filter

Read up on the SSV last night, pulled it apart this morning and everything checks out okay, it moves freely, minimal sludge/gunk on the valve. Tested with a vac pump and it operates fine. Checked the solenoids and they all operate correctly.

Even though I replaced the plugs and coils I'm going to check them while I have everything apart.

i have the exact same issues right now bro. Except mine makes a screaming noise after 5k rpm. I havent dropped the CAT yet and coils, plugs, wires are all new.

Just finished checking the fuel pump sock, some minor accumulation but it definitely wasn't clogged enough to affect flow. Going to check the coils and plugs again now.

I'm starting to think it may be compression, unfortunately I really can't swing the $$ to get the test done at Mazda right now

sounds that way bud.

but i just got back from about a 2hr drive and when i left the house it was 72F and the car was peppy real nice acceleration strong pull all the way thru but toward the end of my drive it was 82F and the car was feeling sluggish and even hard starts on 2 week old coills.

bad performance in heaT is a very real issue exspecially when its hot out AND your engine bay is at full heat

again i dont know what the weathers like where you are but its summer here
the only advice i have left is get up nice and early when its still 60's-70's out and see if its better

Im up in Canada, the temps have been around 60-80 all week so I don't think the heat is an issue... The car's performance doesn't change despite being just warmed up, or after 40+ mins of driving.

I'm going to try a regular compression tester and video tape (60fps so I can slo mo) the gauge and try to get a read on the rpm while this is happening

Hi, new to this forum as I just got my 8, have had plenty of rotors in the past but none were 8s. Mine has the exact same issue, checked the cat, all good, new plugs next check is the coils. I was also thinking that the fuel pump may have lost its flow or pressure??? Keep me posted on what you find.