Weird Stutter Problem While Driving....

[the_red_pooch]

Well I finally got myself a decent 2g GST, so the 99 RS is just a daily driver now. The car seems to be in great condition except one small problem. I noticed this while cruising at about 75-80 on the interstate. While cruising, anywhere around 3000-3300 is where I noticed this happening, the car acts like something kicks in and it begins to stutter and run crappy. While its doing this "stuttering" I notice a dramatic loss of power, it sounds as if it begins to misfire, slow spool up, and my A/F gauge goes berzerk! I realize this gauge is rather worthless, I could have just spent a few bucks on some blinking lights at wal-mart and would have been just as impressed, but it was on the car when I got it. Anyways, pretty much all of the lights on the A/F gauge flicker on and off and its in sync with one another. If I go WOT while the car is "stuttering" the light that is most red(leanest) flickers darker than the rest of them. This "stuttering" problem only occurs if I hold the throttle in the same position at these speeds for about 5-10 seconds and then it seems to "engage" the "stuttering." Now in order for me to stop the car from doing this, I can either continue to get on and off the gas allowing boost to build a few pounds and then release(this is for preventing it from happening), or I can push in the clutch and let the motor idle down to 2k or anything below and it miraculously just snaps out of it and runs strong as ever and everything is back to normal. When I cruise on the hwy at like 60-65 it doesn't happen unless I shift in 4th and run about the same rpms as I would at 80 in 5th(3k-3.5k). I'm really quite confused as to whats going on here and am rather new to owning a 4g63, although I have been on this site reading about them for quite some time. My profile is updated to the best of my knowledge if it should be helpful. Thanks in advance,
Dustin

 

[alex]

Do a boost leak test!

 

[talonguy91]

Does your car have a 6 bolt swap?

 

[femmeDSM]

Does your car have a 6 bolt swap?

First line on vehicle profile:

Bolt-On Mods
Full 6-bolt swap with 14b...

As for your question...Yes, i would also recommend a boost leak test. Might also want to check the plugs/wires just to be thorough. Do you have a datalogger? Not too sure about the A/F gauge since, as you said, these are basically light shows. If you had a datalogger you would be able to monitor your O2 voltage readings and get a better idea of what's going on.

Sounds mighty Boost Leak-y to me, though

 

[the_red_pooch]

Ok, thanks much. I finally get a day off on Wednesday so hopefully I'll get time to read up on how exactly to do a boost leak test and hopefully get it done. What I need to do is find a new buddy around me who might happen to be a guru in the 4g63's, I could learn alot more alot quicker that way, ! Thanks for the responses though!
Dustin

 

[TEAMONEINC]

I had the same symptons in my ride. I replaced the plugs, wires, and re-circulated my super-sequential. Car runs beautifully now.

 

[dyno_detour]

Same studdering and missing on mine also. Replaced the spark plugs and runs smooth as ever.

 

[fifthgearvtec]

boost leaks sux!