How to test MAP sensor

in open loop cold, the computer relies in RAM till it hits closed loop. then the computer takes over.
i would start by looking for vacuum leaks, fuel pressure and anything not connected. beyond that, you need to look at the o2 trims to determine if the injectors may be clogged or failing..

also, start with the basics and do a compression test to verify the motor is capable of working correctly.

Roy

It only runs rough at start up, after it warms up it runs fine. There are not any check engine lights.

too old for any help from codes. i suggest a shop with a scan tool monitor the sensor readings when it is cold to see which sensor is not reading correctly. otherwise, you may be looking at a computer issue with the PROM failure.

Roy