so I ran into this problem. My 2003 ranger had what I thought was a bad misfire. So I changed plugs, wire, and the coil pack and the motor keeps running rough. So I proceeded to change the fuel injectors and the mass air flow sensor. Now it's running just as rough. It idles and then bogs down until I give it gas. But it shakes the whole truck bad. When I give it gas it sounds like the intake is sucking real hard. Before I changed anything it had a raw fuel smell exhaust. Now it smells like eggs or something burning. I'm getting stumped.

 

Welcome to the forum

2003 Ranger will have the 4.0l SOHC engine, 2000 and older had 4.0l OHV, engines are unrelated, so heads up on Google searches

You have changed alot of stuff so hard to says where the problem may be now.

New stuff is no longer tested and no guaranty it works 100% of the time, so something you changed could still be the problem.

Does engine run the same cold and warmed up?
Or better cold, or better warm

Does the CEL(check engine light) come on when you turn on the key?
And then go out when engine starts?

What did the tips of the old spark plugs look like?
tan or blackish color

2003 has computer plug on the firewall top center, it can get water inside
Disconnect battery and remove this connector, look for corrosion

I think there is also a larger engine wiring connector, also disconnect it and look for corrosion inside