Does anyone know who manufacture MAC air impacts, in paticluar the AW434. My impact has little rpms.

Here is a link for the parts list and a retailer that sell this part.
Parts list: AIRCAT Pneumatic Tools Schematics
Retailer: Power Tool Repair Search Results for 305h 007n
Hope this helps!

A very common problem with most impacts is the incorrect size of the air fittings and air hoses, follow the MFG'S suggestion located in the owner's manual. Most 3/4" impacts need a 1/2" i.d. hose with 1/2" series air couplers. All I.R. impacts have a screen on the inlet bushing that can become clogged with debris and will cause a low power condition, make sure it is clean. If the problem persists disassembly and inspection of the tool will be necessary. Most common problems are damaged / worn motor vanes, bearings, gaskets, seals, scarred endplates. Special note for IR261 the endplates along the edge have small plugs that can deteriorate cause an internal air leak causing low performance.
Follow this link to find the parts list for you model:
http://manualarchive.ingersollrandproducts.com/

Hello.
Put two drops of light machine oil or pneumatic oil into the air inlet connection and then hook up the air line. Run the impact at full throttle for 20 seconds. You should oil it daily, two drops. Too much oil is as bad as too little, as too much oil can close off the ports and cause the gun's operation to fall off.
Best regards, --W/D--

One thing to really look at on these is the condition of the cam, hammer pins, and anvil where the pins contact it. It makes all the difference in the torque if these are worn. Also, check the rotor bearings, condition of the cylinder and seals as well. The rotor vanes are most important on their lenght from one end of the cylinder to the other. A loose fit there leaks a lot of air and looses power

http://www.cp.com/usen/Contacts/industrialtools/servicecenters/index.asp
Chicago Pneumatic's web site offers repair sites,but you'll need to enter your location for help and parts or manuals.

Is this an expensive gun?If not this might be normal.If not the hammer in the gun is what makes it tough,So the hammer is worn out,and may be the cylinder it travels in.Try a thicker oil to see if it helps,or henders the problem.If it is the hammer,you will have to get it fix by a tool repair shop,or find on line,and order and install part yourself.

from any Snap-on tool dealer or MAC tool dealer, u can also order them direct from manufacturer web site, have this gun myself.

well pretty much IR (ingersoll rand) makes almost every impact out there. So you can try to navigate their web site, call sears or if you have a Snap On dealer, or matco, or cornwell, or Mac tools. Just call or check out the snap on website see what the dealer for your area is. Tell them what you got and they should be able to find you a kit. They are in the tool business and keeping mechanics wrench'n .

An impact wrench works in the manner suggested by the name of the tool: through the principle of impact. In order to understand how an electrical or air-powered impact wrench works, it helps to know first how a manually powered impact wrench operates. A manually powered impact wrench looks like a fat screwdriver; on the end where the screwdriver blade normally goes, you can snap on screwdriver bits or sockets.

In line oiler Lubrication is critical to extending the life of your valuable air impact wrench and increase productivity. An air tool that has not been properly lubricated will result in low power output. The usual culprit is a dry motor starving for some oil. Your impact wrench is an expensive investment and you must take the time to properly lubricate it. The easiest and quickest way to make surein line oiler it is constantly lubricated is to install an in line oil lubricator. One of these will insure your air tools are receiving oil every time they are used. In line lubricators attach right into the air hose and you fill them with the correct lubricating oil. (see your manufacturer's specs.). You should also do routine external lubrication through the hammer case grease fitting. A well lubricated air impact wrench will deliver more torque, last longer, run quieter and increase productivity. Don't forget to add an in line oiler to your next impact wrench or air tool. It will pay for itself several times over.