93 2.3l ranger miss @ idle

[RonD]

Not an easy job

Fuel pump/pressure issues usually shows up at higher fuel demand, i.e. highway speeds and loss of power

I think you need to track down why the exhaust side coil isn't working

 

[black_demon69]

I get spark when I pull wires 1@ a time on exhaust side coil
Coil started working when I unplugged the connector and then plugged it back in

 

[black_demon69]

Changed fuel pump in about 45 minutes
Didn't even pull bed completely off just tilted like a dump truck and blocked it up

6 bed bolts
3 filler neck bolts
2 fuel line clips
1 wiring connector
And 1 fuel pump retainer ring

?

Changed fuel pump mainly because it was not holding pressure when off..

 

[black_demon69]

It has an exhaust leak and coupled with a 25 year old o2 sensor I am thinking that this could be the cause of the miss possibly.
What do you think

 

[RonD]

Be hard for an O2 sensor to cause a steady misfire, especially at idle since O2s are not used at idle, under 1,000rpm
O2 sensors fail Lean so engine runs richer than it should, so good to change them at 100k miles, and get better MPG for next 100k

Exhaust leak wouldn't cause misfires either, an exhaust manifold leak will cause O2 to show Lean so engine will run Rich

 

[black_demon69]

It isn't a hard mis and it is random. I have observed that if I Rev it I do get a popping in the exhaust whenggas pedal is released (as if there is unburnt fuel) . Also seems to smooth out when A/C is on and there is a little load. So if I remember that means that the IAC is working because idle gets kicked up and popping when reved up and pedal is released stops as well..

 

[black_demon69]

Finally got more time to mess with this and I just blocked off the EGR to isolate it and see if it makes any difference.. I. Am going to drive it for a few days and then I will report result.

 

[black_demon69]

EGR is @least part of the problem... It runs better and has a little bit more power with egr blocked off so I will have to replace it. Then the only thing left is to do timing belt and see if that is off a tooth or 2.