Stuttering

[Jon_0_3]

when running my car at WOT i hit about 4k the car starts to studder. the car will make a dut dut dut dut and slowly clime rpms. what could this be? happens in 2nd through 4th

 

[fallenauthority]

http://vfaq.com/mods/ICtester.html

 

[Jon_0_3]

its not boost leak.
just did a test when it went on i got some videos of it might have to put the volume up to here it

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[cool_g_83]

"This video is no longer available"

Have you checked your plugs?

 

[talon1987]

Sounds like it might be detention but im not sure, all i know is my buddy had the same problem it would studder at 4k and one day he was just messin around with this other car and he went WOT it started studderin he keeped on it to long and a rod went through the block and pretty much destroyed the head with it to.

 

[GSTdude06]

Turn your boost down and see if it was cause you are running to much boost, happened to me once before

 

[brute]

Just started happening to me tonight. I found this thread while searching...
About 2000 miles on the BPR7ES plugs, gapped to .30" I believe.
Like 1000 miles on the 8.5mm Accel wires.
My boost is set to like 11psi.
No boost leaks, just tested.
Just installed a GM MAF and translator.
Just installed a new Bosch o2 sensor.

 

[green_bread]

what injectors are you running? should you be at -14% correction on the afc at 4000 rpm?

 

[tstkl]

my car kinda did the same thing when it was running really, really rich up top (think 7:1 or richer) but don't go leaning it out like crazy just because that worked for me. Look at your logger and see if your o2 volts are crazy rich on your wot pulls, and if they are, you need to lean it out, but don't go by a specific volt, just use it as a guide. If its at like 1.0 volts, your rich as hell, if your at or around .91 (2g) look at knock and stuff to find out how rich/lean you are. don't set it to .91 though and tune from there, start tuning once you get close to that value (like .93-.95)

again, you might be too lean too, and it might not be your tune at all.

New plugs can be bad.

 

[brute]

But my plugs never did this after I put them in. The stutter just started after I put a lot of new things in.

 

[92awddsm]

I agree with tstkl. It sounds more like a rich condition than anything. I had the same problem when my fp gauge shit the bed. Made some changes, set base fuel pressure, and then it did the same thing. Come to find out, my fp gauge was reading 40psi but the new gauge showed it was more like 60 psi base pressure. My car ran fine until the the onset of boost and then the stuttering started.

 

[spyderturbo007]

What's up with your TPS? Was this a multiple gear pull? Right around the point you are taking about ~4300rpm, you can see your TPS drop from 100% to below 80% and your SAFC corrects changed from -16% to around +5%. That's going to cause a hell of a studder. Did you take your foot off the gas?

 

[92awddsm]

What's up with your TPS? Was this a multiple gear pull? Right around the point you are taking about ~4300rpm, you can see your TPS drop from 100% to below 80% and your SAFC corrects changed from -16% to around +5%. That's going to cause a hell of a studder. Did you take your foot off the gas?

The only time the tps changed was on the gear change or when he let off and yes, if you listen, it was multiple gears.

 

[timloomis]

Gap your plugs down to .028.I just had trouble with my maft,I believe the gm maf went bad on me.It ran like crap a lot and only did it in a certain rpm range.