Originally Posted by sneary

Ok guys im stumped right now on this one. I have a 03 4.6is with just over 280,000. The vehicle fires up and runs at about 1000 rpm but once the secondary air pump shuts off the rpms drop down to 300 rpms. Itll run forever sitting still but once you give any gas and release off petal the rpms drop to 0 and no longer running. So far i replaced a few things and did a some routine maintenance on it. I did valve covers, valley pan, oil separator and hoses, CCV, replaced cracked vacuum lines, MAF, spark plugs, and lastly the throttle body. The engine runs very smooth and I do most of the work on it myself but this time I feel a little defeated lol so looking for some insight. Any suggestions???