I made a DIY for this awhile ago and it seems this pops up every now and then, so if a mod could make this a sticky here that would be awesome, thanks guys and gals.
1991-1991 SOHC Intake Tools Needed:
-phillips head screwdriver
-flathead screwdriver
-18G wire (positive and negative)
-18G wire connectors
-Wire Crimps
-Late 80's early 90's Chevy Cavalier, Pontiac Sunbird TB cover
-Any intake designed for a first gen DOHC, I used Injen
-3" wide by 3" long Exhaust Piping (Autozone or the like)
-3" to 3" rubber connector (any plumbing supply store)
-3" to 2" rubber connector (same)
Step 1
After removing your stock intake and tubing and disconnecting your AIT sensor (this is the sensor on the front part of the intake near the filter that stands for Air Intake Temperature sensor) Disconnect the negative battery terminal. When you reconnect the terminal after install this will allow the car to adjust to new air flow.
Step 2
Take your TB connector that you picked from one of the aforementioned vehicles above (found at any pick your parts yard) and make sure you get the screw and ring around it so it mounts to your car. It is a DIRECT FIT, no modification of the TB is needed it simply lays over the TB and is connected by the ring, perfect fit. This item has a wide opening at one end and bends 90 degrees to another open end and it has silver lines on it seen in the first picture below on the left hand side.
Step 3
Take your 3"x3" rubber connector and your 3" to 2" rubber connector. Using the 3" short piece of exhaust piping connect the two rubber pieces tightly together and tighten with either phillips or flathead screwdriver. Again in the first picture below you can see them connected.
Step 4
Connect the 3" to 2" connector to the new intake. You should be connecting the 2" side to the piping. Intake pipes are typically 2.5" at this point, some are three so be sure to know what yours is. Tighten the clamp and your ready for step 5.
Step 5
Now connect the whole unit using the 3"x3" rubber connector to the TB cover that you put on earlier. If the rubber does not stretch enough then warm it up with a heat gun or hair dryer slightly to allow it to stretch and tighten with a screwdriver. Almost there.
The completed assembly should look like this when you are done http://memimage.cardomain.net/member...19_41_full.jpg Step 6
Give your AIT sensor a cut. Determine the amount of 18G wire needed, I used approximately 6" and then using the wire connectors crimp the AIT sensor back together. This allows the sensor to reach the hole made for it on the intake. Some people do tend to just place the AIT sensor to the side, but this is not good for the car since it cannot properly determine air flow rates thus not giving you any benefit to having the intake system.
Step 7
Check your work, and reconnect the negative battery terminal. Start the vehicle and let idle for approximately ten minutes. This will give the car time to properly adjust to the new air flow. Now your done and your system should look like this. Enjoy!!!
http://memimage.cardomain.net/member...19_56_full.jpg
Any further questions or comments please feel free to PM me.
DIY: 1991-1994 SOHC Intake 
Linear Mode
