90 ranger intermittent sputter at take off sometimes stalls, but starts right back up

[bhorner0]

I have 1990 2.3L 4cyl DIS ranger with 8 plugs. Truck runs great at idle. Just recently it started sputtering, bucking intermittently during take off. Sometimes when I let off the gas to slow down it bucks. It has stalled out completely twice now when slowing down, but it starts right back up. Again this happens intermittently and doesn't seem to be correlated to any specific speed or after long or short drives. The symptoms are similar to having water in the gas which is what I thought it was at first but have been through that tank already and it is still happening. Any thoughts are greatly appreciated, as I would like to diagnose the problem before just throwing parts at it. Thanks for your help in advance.

 

[bhorner0]

Update. just replaced plugs and wires. Still idles fine. Now stalls immediately under load. Fuel filter or cat?

 

[scotts90ranger]

start with fuel filter, maybe take the ignition module in to a parts store to be tested.

Before you spend any more money other than tune up stuff, pull the codes, the procedure is on the tech library under EEC IV diagnostics or something, follow the analog volt meter method just forget the volt meter and sit in the cab and count the flashes of the check engine light.

 

[bhorner0]

Changed fuel filter. No change, same symptoms. Pulled codes using volteter method. Getting code 122 (TPS sensor). Checked volts to plug end about 5 constant (what it's supposed to be.) Checked volts at tps itself and at 1.14 closed and 4.67 WOT. Low end is a little high (supposed to be at .9 but real close). Should I still change TPS?

 

[Insanejughead]

Check the full range of the TPS with your analog meter. If at any point it has a break or fluctuation in its sweep, it's causing the computer to adjust how the engine runs.


Say, if you're at a 1/3 sweep and it blips down by a fraction of a volt, then the computer is going to adjust fuel delivery according to the error in the sweep.


So, if it gets to 1.5v and then jumps down to 1.2v, your computer is going to lean out your injectors, and that will cause it to run like shit.

 

[bhorner0]

Checked full range of tps with analog meter as well and the needle made full smooth sweeps with no sudden drops throughout the range of throttle motion.

 

[scotts90ranger]

try to adjust the idle point until you get to .9v and see how it runs, or unplug the IAC and set the idle for about 500rpm, mine used to run odd and wouldn't even run with the IAC disconnected, upped it to 500 with it disconnected and it then idled properly and the voltage ended up being .91 or something similar

 

[bhorner0]

Ended up being a short. Wire harness rubbing steering linkage. Bare wire. Sealed them up and runs fine now. After putting a new tps and stripping two of four throttle body bolts which i had to heli coil. Also had to remove valve cover to heli coil so new valve cover gasket and throttle body gasket. She's good now though Hoping for another 100,000 at 145,000 now.

 

[dberge0]

@bhorner0

I had the exact same issue you did on my 97 2.3 dual ignition. I replaced the spark plugs wires and both coil packs. One of my technician found the Crankshaft position sensor wire harness was bare from getting hot. Replaced the wiring harness and heat shielded the whole wire. The symptom immediately went away. Now 3-4 months down the road the symptom has returned!
so which wire was it by the steering column did you have an issue with?