Ok I'm still having problems with my 98 Ram 1500, 360 magnum, auto, we done been through 4 Distribitor Caps & 4 Rotors & still hasn't fixed the problem.

We know it's not the new engine.

When we crank the truck, it idles weird goes up & down, up & down, ect, ect almost like it is starving itself for fuel.

Now my father says that when he put it in gear it was stumbleing very bad, but the mechanics that put everything in say that the fuel pump was working great good fuel pressure & everything.

We checked everything else, Plugs, Plug wires, 4th Cap, & 4th rotor and they are all fine

The check engine light has finally come on and the first time it was P0117 (engine coolant temp circuit Low input), P0118 (engine coolant temp circuit high input) & P1391 (don't know what this code means).

Now the check engine light has come on again and now it's showing P1391 again, but now the secondary code lights O (oxygen sensor monitor), C (catalyst monitor) ,OH (oxygen sensor heater monitor) but the first time they didn't show on the check engine light. Some say it's my loud exhaust because it has no back pressure & that fuel injected vehicles have to have that, but I have mufflers on it they are 12" glasspacks but they give alittle back pressure, but they will come off and some 24" glasspacks & a H pipe will be going in.

I'm just woundering if my computer hasn't just gone nuts or something.

What does P1391 code mean could I possibly have that death flash or something?

any help Thanks

 

Have you changed the 02 sensors? Mine would hardly run and most of the time die, but when I put in the new 02's it runs perfect.

 

Code 1391 is a vehicle specific code. You have (or had) an intermittant loss of the crankshaft position sensor signal. That's where I would start. Don't condemn the ECM too quickly. If the crank sensor is crappin' out, that will mess up your timing which in turn will mess up your idle and temperature. I agree with DodgeRam2500CTD, test your 02 sensor(s)too. Also, look for major vacuum leaks and not necessarily in jsut in tubing. Check any and all intake gaskets. A leak there can cause the engine to surge as well.
Hope this helps.
WC