misses out or shuddering

[mi240sx]

With gas prices going up I decided I would do a tuneup on the car, I went to the number 1 resource, this web sight to find out what would help the most. So I swapped out my CTS and 02 sensor, checked the timing. I got into the car started it, went for a test drive. Now when I get too about 5psi on boost, the motor misses out, shudders what ever you call it. So I did another search, it said to check for vaccum leak or leak on pipes between turbo and intake, found nothing. I put the old CTS and 02 sensor back in, still doing the same thing. I checked codes there are none and just for grins reset ECU, still the same problem. Driving at 65 or 70 mph on level hiway , my vac gauge is reading 10 to 11 . I wondered what others are reading, I've checked connections, everything. Also, If you hold your connector for 02 sensor up to where the wires are coming out of the plug that go to the 02 sensor, what colors, in what order i.e. white-red black, white-black red??? SR20DET

[0wn3r]

what's your vacuum reading at idle

from what i recall, 10-11 sounds ok...but I know idle readings better than cruising speed since the throttle can mess w/ ya

any check engine light?

[Hijacker]

Hmm...going through some old posts to answer the O2 sensor question, I'm coming up with a ton of mixed results.

Mst people report that the sensor wire is in the #1 pin position, but my manual lists it should be the #2 pin, and #1 should be the heated element 12v switched power. Pin #3 would be the ground for the heated element. White should be signal and red should be heated element.

Check your MAF plug and your CAS plug to make sure they're seated properly.

[mi240sx]

Hmm...going through some old posts to answer the O2 sensor question, I'm coming up with a ton of mixed results.

Mst people report that the sensor wire is in the #1 pin position, but my manual lists it should be the #2 pin, and #1 should be the heated element 12v switched power. Pin #3 would be the ground for the heated element. White should be signal and red should be heated element.

Check your MAF plug and your CAS plug to make sure they're seated properly.

I'm trying to keep from destroying my wiring that I did when I did my swap, before I do I need to get my FSM and meter out and start checking resistance and voltage on some of the components. I'll also have to check and see what vac is at idle, I always seem to remember vac being good, I'll get back with findings.

[mi240sx]

No engine light, idleing vac 19.5

[0wn3r]

seems perfect. i checked my readings when cruising at 65-70 and they were right about at 11-15inHG as well.

[mi240sx]

Is there a vaccum line going to the IACV, looked at FSM and did search here, but found nothing. I was having the problem of getting to about 5 psi boost then it would shudder, I replaced the spark plug NGK Iradium # 7 heat range, went for a test drive now it shudders at about 10-11 PSI. No boost leaks, no codes(not everything is covered by ECU codes), I noticed around #3 cylinder injector a small stain from the injector , O-rings will be replaced next and I'll check injector operation. This all started out by just trying to improve gas mileage by replacing the CTS and 02 sensor, it was running fine before.