N 12 pulsar missing badley gradually got worse i

Some cars have a vacume check valve on the vacume line that
activates the air duct to open and close . If the vacume is not right
it will not work properly . If the vacume check valve is ok then check
and make sure the heater core is not clogged up

It sounds like You will have a vacume line off

Check the hose betwen the
air filter and the motor, could be loose or cracked.

please check your vaccum lines for leaks

have you switched or cleaned the EGR valve sounds like the advance in the EGR is not working also check the vacume line to it .

look for a diagram under the hood follow the route for each vacum . you have a intake leak take your time and go over each side of the engine even plastic air line could be cracked

check for vacume leaks on intake and other vacume hoses. random misfire is also usually a clogged fuel filter or pressure regulator. could also be a cam or knock sensor. are their any trouble codes.

hey there i cant tell you what you are missing but i can tell you how to disengage the front wheels . ok you have a vacum line that runs right under the battery and a line that comes up from the front diff. to the same place ( you may have to remove batt and batt tray to get full access to this) un bolt it and temporaly put batt and batt tray back in start it up and decompress this and see if it comes out .... you should here clunking noise if it goes back in ... if thats the case just pull that big vaccum line off .... to test get all four tires off the ground and have some one put it in drive but dont hit the gas it should turn on its own ...if that dont work check the cable that runs down to the differental

to much fuel pressure or bad vacume line

There is a vacum powered actuator on the front differential housing on the passenger side. It gets it's vacum from two valves mounted on the firewall just behind the battery(to left). The white line feeds manifold vacum to the valves. Check for vacum at white line with engine running. If no vacum there is a break in line from manifold. If vacum check the pink and blue lines by applying vacum to each one. The vacum should hold. If not check lines from valves to vacum actuator. Most likely it will be the actuator. If both lines hold vacum check valves. Remove electrical connectors from both valves. Connect a wire from one of the terminals of the valve to ground. Touch a wire from the battery + to the other terminal of the valve. Listen for a clicking sound. If no sound valve is bad. Replace valves(s). If this doesn't lead you to the trouble it's probably a mechanical problem inside the differential. However most likely there would other noises.