If you guys can help me ill love you forever. I have almost givin up on my truck and its not looking good. I am replacing my oil pump. However the guy at the auto parts store ran a diagnostic and revealed misfire cylinder 4 and a random misfire. But he said this could be the oil pump. whatever i need some help/advice on how to install this SOB before i blow it up and buy something else.

 

have you checked the other reasons it could misfire? Cap, rotor, wires, plugs?

 

Yea new plugs about 3-4 weeks ago.I dunno wtf to do. I have givin up.

 

yeah ive never heard of an oil pump causing misfire. if it did F**k up, your motor would be dry and it would be dead .

like motorbreath said, cap rotor wires, are common misfire items.

 

It's not the oil pump but the oil pump/distributor bushing in the block that can cause misfire.
If the bushing is really worn the distributor shaft flops around and the rotor doesn't line up properly with the cap.
I would be returning the pump if I was you. Don't let the parts guy diagnose your car!

 

i know you said you had new plugs, but have you taken off the cap and rotor and inspected them for cracks and corrosion? also check your plug wires, make sure none cross. Wires that touch can interefere with each other and cause a misfire.

+1 on what rabbler said also. give that a check after you check all the above.

 

check the TSB on plug wire routing:

http://dodgeram.info/tsb/1998/18-48-98/18-48-98-v8.htm

A misfire on 3 and 4 means you could have crossed wires, check that too.

It is possible that your Catalytic converter is clogged, but that typically causes a misfire on the number 7 and 8 cylinders.

 

If it is any help I can second what rabbler is saying. I had a misfire in my truck two weeks ago. To be sure what was going on I took it in to the dealership and had a computer diagnosis done. Well mine simply needed wires plugs rotor and cap which I promptly changed myself, problem solved. However while I was talking to the mechanic he told me certain years not 98,s have been having a problem with the distributor bushing going out, causing slop in the gear. This in turn causes misfire. Apparently a real common problem. Not saying this is yours but it may be worth a look.
Hope this helps.

1998 4x4 5.2
Longbox 79,000

 

I've only seen it a few times and they were on very high mileage motors or ones that were neglected.

 

I love you guys. If you ever come to alabama stop in huntsville and ill buy you a beer. After taking off the oil pan and draining i realized my truck had about 2 quarts oil probably resulting the oil pressure failure. Took oil pump back got money. Friday new wires new rotar button. I put a quart of lucas and 4 quarts oil and boom oil pressur above 40. Thanks guys. I really appreciate it.