i have a 96 Ranger XLT 2wd that i use as my daily driver that is being a bit "hit or miss" lately. some days, it'll run AWESOME and the power if pretty damn good for being only a 2.3L 4 cyl, but most days, it's piggy, has an intermittent miss, and the occasional stutter at a stop sign when i go to take off that gets me a little worried. the strange part is that it seems like it runs the BEST when it's wet/raining. when it's nice out, it's all lazy. anyone else have this problem?

things i've done so far: Exhaust (went from flowmaster 40 and side pipe to thrush welded with complete exhaust), plugs and wires, and a k&n air filter (not cold air)

 

I don't know the newer 4 banger specifically, but with the conditions youveescribecit sounds like a MAP/MAF issue coupled with a sensor not sensing a warm engine.

Having a cool, wet day coupled with running rich the engine performs well. A hotter, dryer day it is now running too rich.

Just my thoughts.

Josh

 

Did the miss & studder come about after the plugs/wires, or exhaust work, or after some other event, or did it develope slowly over time????

Have you had the computer scanned for trouble codes???? If so, post all of the code Numbers found, as they can offer up good trouble shooting clues. If any sensor is out of tolerance, it should be flagged by the computer with a trouble code.

Oiled Cotton gauze or Foam type air filters are known to foul the MAF sensor, so maybe consider removing it & cleaning with CRC non residual MAF sensor spray cleaner. Let the sensor cool before cleaning, don't touch the sensor with the spray wand. Keep it squeeky clean on re-installation.
If that fixes it, re-install the specified Motorcraft air filter. Our stock engines are factory tuned & aren't air starved, so we don't need air intake mods.

Your exhaust system was factory tuned also, so if you've increased the pipe size, or adversely changed back pressure, you may have messed up the exhaust tuning velosity & scavenging.

I suppose on the studder on take-off, that an acting out TPS sensor may belong on the suspect list, along with a dirty MAF sensor.

On the intermittent miss, when you changed plugs & wires, did you use the factory specified fine wire iridium enhanced center electrode, with platinum sidewire design, or at least double platinum plugs & did you check the plug gap & end to end plug wire resistance before installation???? Did you use the specified factory plug wires????

 

the miss started not long after i bought the truck. it's been progressively getting worse, and i had suspected an IAC but it just didn't seem to fit. the only thing in the exhaust that isn't factory is the muffler, but it had a flowmaster 40 on it when i got it with 2.5" pipe and that fell off and i put a thrush welded muffler with the 2" factory exhaust. the miss and stutter has been getting progressively worse. it was tolerable at first, but now it's just plain annoying. i changed the plugs and wires when it first started the miss and found that one of the wires was broken and all of the plugs were just about shot.

also, the engine is throwing no codes at all. check engine light never came on.

Edit: The plugs and wires had helped a bit and it ran great for a while but it's starting to act up again. the old plugs showed lean (electrode was almost burned completely away).