Major Lack of Power

[FORDGUY66]

I have a 1997 Ford Expedition 5.4L 4x4 with 150,000 miles on it. I was having some misfire issues which lead to replacement of my injectors and coils. After I replaced the injectors the truck wouldn't start. It would crank and crank then back fire. Finally tried starting fluid and it fired up but ran rough. Thought it could be air in the fuel rail and didn't think much of it. It is still idling rough, I am getting really poor fuel economy (around 5mpg on a good week) and it has lots of troubles getting up to speed and maintaing it. When on the freeway in order to maintain about 65mph it sits at 4000rpm and the speed still drops. I have checked vacuum lines and used a vacuum pump to test them. All were ok, replaced the elbow on the back of the intake manifold as it broke when trying to remove it. There was a small vacuum line between the firewall and the battery on the pasenger side that was broken and I fixed that.

Thought it could be the mass air flow sensor so I checked that and I was getting power to it, and I replaced the sensor but still no luck. I have also replaced the o2 sensor on the pasenger side because it threw a code for the circuit being too slow. As of right now, I am getting P0171, P0174, and P1131 which are all related to the truck running too lean. I have removed the cats and it smells like raw fuel coming out of the tail pipe. I have ran fuel pressure checks and they are all between the specified ranges. I have tried spraying starter fluid and listening for an increase in rpms but no luck. I have tried spraying water from a squirt bottle to see if steam comes out of the tail pipe or the motor bogs down and no luck either.

I had to replace the head gaskets prior to all of this and replaced the plenum and intake gasket at the same time. It ran fine after that except for the misfire but I am stumped on where to go from here. Why would new injectors and ignition coils make it run worse?

Any help will be very much appreciated.

Thanks,

Matt

 

[joezek]

I would triple check that you have the correct part # injectors..what part # did you install?

 

[toms89]

Are you sure you put the proper size injectors in??

Smelling raw fuel and lean cel's points to misfire. Misfires will dump raw fuel into exhaust but register as lean as the O2 sensors register the oxygen in the exhaust not fuel. Misfire dumps unburned O2 in the exhaust as well as fuel.

Misfires can be caused by excessively rich or lean mixtures as well as the ignition system.

 

[FORDGUY66]

Standard Motor Products FJ713 Fuel Injector. They are new multi-port injectors that match the original motorcraft ones. Rock Auto sells them but I found them cheaper on Amazon.

 

[FORDGUY66]

It seems like it would be misfiring but why? Spark plugs are new iridiums replaced not even a year ago

 

[toms89]

Dont know what to tell you but it sounds to me like the injectors are the wrong size..... possibly too large.

If it was this way before the injector swap I would look elsewhere but....

Double check all your work and make sure all vacuum lines and electrical connections are secure..

Try resetting the pcm if you did not as it may have adapted to the old injectors and the new ones are off significantly from those??

 

[joezek]

maybe one or more injector base o-rings are missing, torn, or leaking?

 

[FORDGUY66]

I have disconnected the battery numerous times in hope of resetting the PCM and have deleted codes off of it and still no luck. The injectors are fully seated and the o-rings were new when I put them in there and I lubed them with some spit so they would slide in easier ha. I have sprayed around them with water and starting fluid to see if it would change and still nothing. Before I replaced my mass airflow sensor I unplugged it while it was running and there was no change to the idle positive or negative. That's why I replaced it.

 

[toms89]

I have disconnected the battery numerous times in hope of resetting the PCM and have deleted codes off of it and still no luck. The injectors are fully seated and the o-rings were new when I put them in there and I lubed them with some spit so they would slide in easier ha. I have sprayed around them with water and starting fluid to see if it would change and still nothing. Before I replaced my mass airflow sensor I unplugged it while it was running and there was no change to the idle positive or negative. That's why I replaced it.

It will start and run fine for a period of time as it initially is not using the mass air signal. Do not remember the specifics as far as time and conditions...

There is also a load with failed mass air table the pcm uses if the mass air signal has been lost or considered bad. It uses throttle position and rpm to determine approximate load. But this almost always run noticable different and will set cel.

 

[FORDGUY66]

Ok. What can I do as far as solving these misfires if that's what is causing all of this?