u have a cylnder low on compresson
its prob the thermostat i had the same problem with my uncles
Im having the same problem. Either the cold start things bad or the timings off or both...
If you had the battery disconnected then the computer has to relearn the optimum efficiency for everything that's going on. If you didn't disconnect the battery, then you should do that for about 30 minutes and clear the computer out so it can relearn with the new MAF sensor connected.
I am having the same problem sounds like the knock sensor OBDII code P0328 or P0327 Try looking up CMU codes using OBD It also could be a clogged Cat being cat has little effect until after exhaust has warmed to a certain point.
Wait until it warms up and melts
bypass the the line that runs into the radiator. witch is a trans oil warmer. reconnect both lines together
It will until the coolant warms up.
more than likely a valve!
If sit has a carb. perhaps choke is not releasing fast enough - causing it to run too rich until warm up
try 92 octane or higher.
I have 1998 a Lincoln town car with the same problem.. It idles rough when you start, then smooths out once it warms up and you give it gas. From what I am reading its either an oxygen sensor or you have vacume leak in one of your hoses by the manifold.
Often a knock when cold is caused by piston slap, which is pistons rocking in the cylinders until they expand in size when the engine warms up.