If you were running half boost and the check engine light came on, then you may have been running rich. Running rich will most likely cause the manifold o2 sensor to get covered in unburned fuel. That will throw a code, but it doesn't mean the sensor is bad just malfunctioning. You can usually just clean off the sensor, and it will work perfectly. But hey, now's as good a time as any to move to a wideband!

 

what is a good way to clean the sensor?

 

I dont know if youve fixed this yet or not since its been awhile but gauranteed its your intake manifold gasket

 

What I did to try and fix the problem is I got all metal ic piping. going from te turbo all the way to the intake. I also put in a Greddy type s bov and booste gauge. It kinid of fixed the problem. After I had the pro shop put the bov and guage in I could get up 15psi everynow and then. now I cant get higher then 11 or 12psi. my question now is that when I have it at 11psi or so and keep the gas down it feels like the car is pulsing. is this normal or shoud I start to look for a new turbo( that I dont have the money for)?

 

It may not be your turbo. Do you have an air compressor? If so you should do a leak test. What you have to do for that is go to like Home Depot or Lowes or something like that and get a hard rubber coupler about 3-4 inches long which has the inner diameter equal to that of your turbos outside diameter inlet. Follow me? Now you need a pvc cap piece to fit inside that hard rubber coupler. Then clamp it in. Now you need to put a schrader valve, like your car tire valve, in the middle of that pvc cap. Drill a hole in the middle of the cap and thread it in. Do you have a mental picture of what im talking about??? Now put the open end of the coupler onto the inlet of your turbo. Clamp that on. now hook up a compressor to that schrader valve to pressurize the system. Only hold it on there for about 8 seconds then take it off. Now squirt a little soapy water on all of the intake system, if the leak is big enough you will hear air escaping. Now just track down the leak. Do you know all of this allready?????