Low or no idle and hard starting
 

A few weeks ago I bought a 97 passat with 2.8l VR 6. When I got it home I had to change the thermostat. Then I installed a new radio. I was heading to work and hit a pretty large bump. I lost power and it took awhile to restart. I finally got it home. It was difficult to start and would not idle when I could get it started. The only way to keep it running was by pumping the accelerator. If I do this I can keep it running for awhile, but get a lot of backfire like noise rough running and mis firing. i have replaced the plugs and wires, the coolant temp sensor, fuel pump relay, a hose on the SAI and broken intake boot. The only code returned from VAG-COM is for low voltage from the MAF. After all this it now starts, idles around 500 rpm for about 15 seconds and dies. I can keep it running by wildly pumping the accelerator. The idle improves some when I can get it to operating temp, but it is rough getting there. I am thinking now that something was knocked loose in the dash or center console near the radio, but I don't know what. Any help would be greatly appreciated.