[SSDan]

Originally Posted by SuperSound

There's also a booster between the tank right? Thought I heard that.

Sent from my SAMSUNG-SM-G920A using Tapatalk

There is a traditional electric low pressure pump in the fuel tank to push the fuel up to the high pressure pump at the engine.

[avalonandl]

direct injection engines need time to pressure the fuel off a pump which is CRANK driven.....

It takes longer.,,, these systems are up at 2200 psi.

[SSDan]

Originally Posted by avalonandl

direct injection engines need time to pressure the fuel off a pump which is CRANK driven.....

It takes longer.,,, these systems are up at 2200 psi.

Yep - you're right other than the pump is CAM driven.

[avalonandl]

Originally Posted by SSDan

Yep - you're right other than the pump is CAM driven.

Sorry- how about engine driven.......

[chrest]

Searched for this and stumbled upon this thread. My car straight has a surge when cold. Like it will almost buck when accelerating until its warm. So far this is only when it's been sitting for a bit. If it's cold after driving t all day it doesn't do it. But when driving it cold after sitting it's not right... wtf

[2K16SummitSS]

Originally Posted by chrest

Searched for this and stumbled upon this thread. My car straight has a surge when cold. Like it will almost buck when accelerating until its warm. So far this is only when it's been sitting for a bit. If it's cold after driving t all day it doesn't do it. But when driving it cold after sitting it's not right... wtf

I can almost guarantee you are in the beginning stages of what I went through.

See here...
http://www.camaro6.com/forums/showthread.php?t=473052

[chrest]

Originally Posted by 2K16SummitSS

I can almost guarantee you are in the beginning stages of what I went through.

See here...
http://www.camaro6.com/forums/showthread.php?t=473052

just read through your thread. I will be book marking that info in case it gets worse.

I drove it all weekend and never had an issue. so far i have only seen it when it has sat for a few days and it always goes away completely as it warms up.

[nukemustang]

Originally Posted by chrest

Searched for this and stumbled upon this thread. My car straight has a surge when cold. Like it will almost buck when accelerating until its warm. So far this is only when it's been sitting for a bit. If it's cold after driving t all day it doesn't do it. But when driving it cold after sitting it's not right... wtf

I don't remember if mine always did this, or I have become sensitive to it. I have noticed this EXACT thing when the engine is cold, like sat overnight and the first start in the morning. It seems to be fine AFTER the first time I accelerate with any decent speed (greater than the 20mph in the neighborhood), but that first acceleration is a little iffy, sounds like it is misfiring like a champ.

I pulled all the plugs this weekend and cleaned them, still acting the same. I haven't gotten any check engine lights and I hate to drop the car off for the dealer to tell me "it's normal".....

I can post a pic when I get home.

Car has only about 3K miles, BUT it has a lot of idle time on the hour meter before I bought it...

[2K16SummitSS]

Keep in mind that my issues didn't progress to CEL until almost 10k miles, and that is when I was finally able to get the dealer to resolve the problem. I put miles on cars quick. I'm now at 25k and no issues since.

[nukemustang]

well that bites... it might take me a year to get that many miles... if it is broke, I'd rather just have it broken and fixable, then kind of broke and just waiting. I looked on rock auto, injectors are only like $50/each....

[chrest]

Originally Posted by nukemustang

I don't remember if mine always did this, or I have become sensitive to it. I have noticed this EXACT thing when the engine is cold, like sat overnight and the first start in the morning. It seems to be fine AFTER the first time I accelerate with any decent speed (greater than the 20mph in the neighborhood), but that first acceleration is a little iffy, sounds like it is misfiring like a champ.

I pulled all the plugs this weekend and cleaned them, still acting the same. I haven't gotten any check engine lights and I hate to drop the car off for the dealer to tell me "it's normal".....

I can post a pic when I get home.

Car has only about 3K miles, BUT it has a lot of idle time on the hour meter before I bought it...

exactly how mine is. it cleans up fine, but its not something id call normal by any means

[2K16SummitSS]

Yep, mine had a really rough idle through the cold start sequence, but was totally fine at operating temps. This started at about 3k miles up to 9k. Then it started throwing codes and became more unpredictable.

[nukemustang]

This is what the plugs looked like when I popped them out. I pulled all 8 (some on the passenger side are a mutha-%#$). I cleaned them off with a brass brush on a dremmel thinking it may have just been a carbon build up problem causing poor detonation. I am currently also pushing through a tank of gas with a bottle of Techron in it.

[Snrub]

I know this thread is old, but it seemed to stimulate some good conversation. My car is experience intermittent hesitation. It typically happens in cold conditions and always when the engine is warming up. It also has misfires when idling, cruising, etc. It happens some when warmed up, but not a ton. No idea why. Previously I had a CEL. The dealer blamed bad gas (I was running premium) which fouled spark plugs. I was initially bit skeptical of the diagnosis, but accepted it. Things seem to be getting a bit worse, I'm still on the gas the dealer put in the car.

Regarding the conversation about misfires causing CELs, I've monitored and logged OBDII data and I've definitely had non-zero misfires, more than I would have expected without a flashing or solid CEL.