98 explorer 4.0 ohv

[Dnash80]

I have a 98 explorer with a 4.0 ohv and i am having a world of issues. Bank 1 and 2 are to lean, and ive got a cylinder 4 misfire. I replaced coil, plugs and wires, and #4 injector and cleaned up the rest of the injectors and the fuel rail, new gaskets and o rings on intakes and all injectors. Ran good like real good when i replaced the injector, for 2 days then went back to the same old thing. When i hit 35mph it starts shaking and i have to let off the pedal then get back on it and it smooths out some but once im up to like 55-65mph, all hell breaks loose and its like the car is having a seizure. Well i left work the other day the oil pressure guage started acting up went real low then back to normal then jumped then once i got going it stayed in normal. Does anyone have any idea of what it is going on with this thing? i would appreciate the help!

 

[jmd240]

Hello. If you are having the lean codes, you should check your fuel pressure at the fuel rail. Might not be getting enough fuel pressure. Having the misfire on the one cylinder, I would check compression or cylinder leak test to see if there is something wrong with that cylinder. Oil pressure might be unrelated to the other problems, but I would put a gauge on and see what it is reading. Hopefully it's just indicating incorrectly. Hope this helps, good luck.

 

[masospaghetti]

Did you replace the upper plenum gaskets when you had the fuel rail out?

The o-rings between the upper and middle plenums tend to dry out and shrink, leading to vacuum leaks, lean codes, and a host of drivability problems.

 

[Dnash80]

I haven't put a gauge on anything yet but I will,
Some one told me could be my catalytic converter?
Doesn't make sense to me but I'm unsure. Yes I replaced all
The gaskets on both upper and lower intakes. Could the fuel
pump not be sending enough fuel causing the lack of pressure?

 

[Dnash80]

Yes I also replaced the plenum gasket between the fuel rail, it
all came in a set from advance auto parts

 

[08_sploder]

Well i know 02 sensors can cause a loss of power, surging, bucking a plugged cat could mabey cause lean a bank but i agree with checking fuel rail pressure if its good id do your injectors not just clean them. But i will say normally 02 sensors will throw a code. What codes are all coming up?