My car seems to fall on its face around 3500rpm and feels like it finally lets loose around 5800 and starts to run right. Feels like knock or major timing being pulled. Car has 500 miles on it and it holds boost at around 15-16 lbs. It's got 93 in it and is stock with no sel's on.

Another thing...... at cold start it's really loud for about 1 minute then quiets down to a normal exhaust note..... almost like something is bieng bypassed. Coolant temps are around 196-198 and i see as low as 190 cruising. Thanks for any help you might be able to give .

 

your boost levels are fine. And yeah they louder at idle on a cold start. thats normal. Sometimes i tap the gas and it will idle normal. As far as it laying on its face i have no idea why it would do that. your coolant temps are perfect also

 

maybe because ur turbo isnt broken in or actully nothing is broken in yet. you should not take the car over 4k rpms for the first 500miles....read your owners manual but honestly it might just be because the cars not ready to be driven like that yet.

that loud noise would be your direct injection warming up.

 

Don't you have to put miles on these cars before the computer lets loose?

 

yeppers, you do... but from the factory, mine pulled pretty hard all the way to redline... never fell on its face.

 

I was easy on it till 500 miles .... i test drove another car and it didn't do what mine is doing. I was just wondering if anyone else has gone threw something similar. Thanks for the reply's all.

 

Deff not, mine ran like a bat outta hell on the way home from the dealer. I would take it in. Thats what those smucks at the dealer are good for.

 

I'm going to take it in tuesday . I'm gunna pull the battery cable and reset the computer , and prolly pull the plugs and check gap's for now thou. Thanks for the reply

 

i drove my car hard from day one. that is just a myth about tking it easy for the first 500miles. Break your car in the way that you want it to run.

 

I just got mine a few days ago and I have noticed the same thing. It doesn't happen all the time, it seems like only when the car has been running for a while. You can the hear the turbo spooling and the exhaust changes it's note a wee bit. It's only in 2nd gear from what I can tell. Maybe the learn down function pulling timing to maintain hp/tq levels?

 

Try turning traction control off.

 

My car got quicker as the miles went up and I purchased it brand new. When I first got the car it really didn't feel too much faster than my old 6 speed 02 Maxima. I took it on a 370 mile trip (one way) to upstate New York two days after I got it. I must say once I got home (840 miles on the clock now) the car felt like it had 30 more hp. I had it at the track with less than 1000 miles on it and it pulled 101.2mph...at 2400 miles it was going 104mph. I know the weather was cooler but some people are hitting 103-104 in sedans now with 80 degree weather.

My car is louder on startup and first take off when cold. My guess is the wastegate dumps anything from the turbo into the exhaust...making it sound as loud as a n/a 4 banger.

 

itll gte quicker and the exhaust will get louder as you break it in.

 

Fuel is injected on the intake and compression strokes, fuel pressure goes way up, and ignition and cam timing is changed when when it is in cat warm up mode. That is why the motor is louder. It is designed to warm up the cat faster which decreases emissions.

 

Thanks! I've been wondering about this for quite some time.

 

Thanks for all the help. I pulled the battery cable and it was better for about 5 miles and it went back to doing the same thing. The exhaust does change note when it hits the ''bog'' i'm talking about. It almost sounds the same as when you put the choke on other things after the motor is warm (motorcycle, snowmobile..ect ect). It doesn't spit or sputter , it just hits a wall and the pull stops dead. If i mash on it in 1st from a 5 mph roll it won't even squeek the tires with trac off.


One thing i've noticed is how fast the coolant temp rises from a cold start. This car is at 130-40 in no time at all, my sc would take forever to get to those temps.

 

Your Welcome

 

i babied mine for the first 2 months...never really flooring it and never spinning tires..as hard as it was to do that, i've definately noticed the car "breaking in" and i know all cars have diff things about them but that is what i've seen...i have 8000 miles now and my car still suprises me sometimes when i nail it...no worries it might just take a little time

 

The higher idle you get on cold start is a normal start-up procedure the engine goes through, I'd guess to heat up quicker. If you wait about 15 seconds and tap the throttle, it aborts the sequence and settles to regular idle.

 

Thanks for the info

 

If you also listen. You here the turbo spooling up at this time...

 

i bought my 08' at the end of may last year, and yeah the higher rpms are normal, and i never really got on it until after my first two oil changes (1,700 and 3,100) miles, but the couple of times i tried, i had this same "sort" of thing happen... didn't fall flat on it's face, but it's noticeably quicker after about 3-4k miles.... just please baby it (even though it's terribly hard to do) until at least 3k and then slowly start to get on her. it'd be terrible to kill the internals after spending the money on her!!!

 

mine did similar stuff when i had under 500 miles and hot weather. Happened a couple of times. put some easy miles on her, run nothing but 93, then let it rock

 

My car and many other members have experienced the same power loss issue. Some say it may be part of the break in period because usually it goes away after a week or so. Check out this thread https://www.cobaltss.net/forums/show...ght=loss+power, your not the first and no one seems to have a reason for it. Resetting the computer "usually" gets rid of it but in my case it came back a week later. Just gave it a week to work itself out then it ran like a champ again.

 

Thank you for the link! I read all of it and guess i'll ride it out for the next 500 miles or so. I did reset the computer today and it seemed better for about 10 miles but its back again. Eville did your exhaust note change when it bogged down or no? Thanks again!