Strange fluttering and hesitation.....

[714ms3]

So if I am cruising 6th on the freeway and need to pass someone, I have always downshifted to 5th to get around them without a problem.
Recently, when going WOT in 5th at around 3000+ RPMs I am getting a fluttering noise, accompanied with what sounds like a rock pinging around inside the turbine, and massive hesitation.
This noise and hesitation will occur for a couple of seconds, then the boost picks back up and the car accelerates normally.
What could be going on here? Compressor surge? Vacuum leak? Everything on the intake/inlet side seems firmly secured?

 

[Sport6]

The rocks pinging noise is actual knock.. if you are on stock plugs or have had them for a while, it might be a good time to change them out. If you feel that again, take your foot off the gas immediately. Knock (detention) is the main cause of rod weakening and could eventually cause engine failure.

 

[714ms3]

The car has 18000 miles on it. Regularly changed oil every 4000 miles. All highway miles.
I have not beaten on the car or anything. Would knock still cause the hesitation/loss of power?

 

[Sport6]

Short trips can cause the spark plugs to get build up on them, also I see you have the AP which Cobb recommends having step-colder plugs for.

The loss of power is the engine cutting back on timing because of the knock.

I would change out the plugs just to make sure, even check the gap on them because that could cause the hesitation if its too big (should be .028-.032").

 

[714ms3]

Sorry, I have not edited the sig, but I got rid of the AP months ago. I only had it for a month.
But I will change the plugs and see what happens.

 

[Speed3Max]

but why WOT at 3k?

 

[Darth Vader]

Why not?

Change gas stations recently or fill up with a lower octane # last time?

 

[714ms3]

No new gas or anything. Oil was a little dirty - just got that changed.
Also, what is wrong with starting to get on it after letting the turbo spool up after hitting 3k?

 

[squidmotion]

could you be suffering from a boost leak somewhere? maybe a loose clamp on the intake side or something?

 

[714ms3]

I double and triple checked everything on the intake/inlet side. All looks well.

 

[8.5MS3]

bpv may need regreasing
fuel pump may be shitting the bed
may be knocking


you need to get a DH and take a look at whats going on

 

[Jchouin1]

Why not?

Change gas stations recently or fill up with a lower octane # last time?

Why not? You kinda have 2 choices going wot @3k.
1. Stay stock.
or
2. Learn to build engines.
Not fun to hear, but holds a lot of truth.

 

[MSMS3]

I'm not sure WOT at 3Krpm is that much of a problem. WOT at below 3K is a BIG problem. Not trying to cut it too fine, but I'm sort of between you two guys on that point. I try not to go WOT below 3,500 rpm, because by then I can build boost better without turbo lag and am clearly on the other side of the huge low rpm torque spike that happens when you first come up on boost down that low.

Like a "good" politician (oxymoron) would say: I come down firmly in favor of both sides of this issue. lol.

And yes, I'd be exploring fuel, or even something as simple as a dirty air filter. Check the simple obvious things first before assuming the worst.

 

[714ms3]

I should not have said WOT at 3K, but starting to get on it with my foot all the way down at about 3.5k. I know not to stress this motor at low RPM's, but I am not driving it any differently than I have in the past.
I think that I had dirty oil and a bad tank of gas, as the problem seems to have subsided, but we shall see.