I picked up a 1997 dodge dakota 3.9 with 180k and it has a random missfire code p1391
It is running like **** sounds like its running on 3 cylinders backfires threw the intake when u give it gas sometimes The guy i got it from said he changed the

Coil,crank position sensor,cam sensor,distributor,map sensor, and a new Computer and a ton of other things what else could do this i have looked around it is a common issue but cant seam to find anything.

 

I dont see plugs or wires listed as being changed. Wats the condition of those items?

 

Yea the plugs wires rotor and cap where all replaced compression is good aswell

 

What is the fuel pressure suppose to be? i dont have a manual for it yet

 

Another thing i noticed is the rpms gauge does not work other ones do tho on another car i remember it was connected to the crank sensor and cam sensor so could that mean one is bad if its the same on dodge?

 

The fuel pressure should be about 49 psi.

The tach runs of the PCM.

 

He gave me the old pmc plugged it in still no rpms gauge even with the new one still doesn't work i think this is somehow connected with it not running right will have to dig into it more tomorrow.
also the guy replaced the whole distributor how do i know if he put it back in the right spot or not is there a way to check? also want to check the timing chain how are the marks suppose to line up?

 

He pulled the distributor and screwed up the fuel sync. That's why it's running poorly. Let your dealer reset it with a scan tool. It's the easiest and fastest way.

P1391 is not a random misfire code, it's a loss of cam or crank position sensor.

Make sure that OEM Dodge sensor have been used. Lots of the aftermarket ones are garbage.

 

will check the crank sensor and surprisingly i dont have any dodge dealers near me is there
any other way to do this?

 

You need a really good quality scanner to set it. A good shop should have it.

Not a code reader, a scanner. It's reading live data to set it.