Ok my 94 Ranger has been giving me some issues lately. About a week and a half ago it started acting up. First I will explain the symptoms then I will go into what I have already looked into.

It runs sluggish on takeoff and as soon as you get the RPMs up to around the three grand range it takes off like it was just given a shot of nitrous.

Sometimes when I am sitting at an idle I can smell gas. I have checked the codes and it does come up with a code saying that the left bank is running rich. I have already replaced the coil packs as well as the air charge temp sensor and the coolant temp sensor as the codes for both popped up at separate times saying the voltage was too low for them. The codes for both have since disappeared and with the coil pack being new nothing has changed.

I also ruled out vaccumn as being a problem.

I checked the fuel pressure and it is running between 35-40 psi.

Everytime I replaced something it would act for a short amount of time like the problem was solved and then within about a couple miles of driving it would return. I should also mention that once the "nitrous" effect occurs it runs pretty good. But as soon as you have slowed down and get back to lower RPMs and try to pick up speed it gets the sluggishness again.

Once other thing I have tried is cleaning the MAF sensor. It is barely over a year old and the code reader isn't picking up any codes from it.

My exhaust doesn't seem to be getting hot (atleast not enough to glow red at night) However it doesn't seem to be blowing out the tailpipe quite like it should. (kinda sputters when someone is hitting the throttle. The cats have already been punched out previously and the only thing I can think of is it possible that the muffler (original) is plugged causing the issues I have described?

I have already sank money into parts that didn't solve the problem and I really don't want to continue wasting money on something if it isn't gonna help. Any opinions on this would be appreciated. Thank you in advance.

 

My 1998 4.0 was doing the same thing - sluggish and missing until the rpms got over 2200-2300 and then taking off like a shot. Everything checked out on fuel delivery, coil pack resistance, new wires and plugs, etc. Everything I tried seemed to help briefly and the problem would return. Eventually I went back over the basics and my spark plug gaps were all over the place. Had I not checked? Who knows? Anyway, reset gaps to .050 and now I cannot GET it to miss! Best it's run in months. Check that and see if it helps.