:(2004 hemi developed bad miss someone said broke valve spring
To find out if you have a broken valve spring you need a vacuum gage. Install the gage to manifold vacuum port that is located below or past the throttle plate. After attaching the vacuum gage to the proper port, start the engine and observe the gage. A normal running engine will have a steady gage reading of about 18 inches of vacuum.
A broken valve spring will cause the gage to fluctuate badly but a steady fluctuation. If you observe this then you need to find the dead cylinder. Remove the valve cover and go to that cylinder and check out the valve springs. One of them is most likely broken.
Another way is the old compression test. Check all the cylinders and compare the results. If you have a bad or broken valve spring the compression reading will be very low.
If you need more assistance on this problem feel free to ask, we will be glad to help.
:)it was broken valve spring , it was 2 man job .really hard to work on hemi's had to remove brake booster to get at it.......