Hello Everyone,

I've been lurking on the forums for the last few days after picking up a 1994 Dakota 4X4 5.2 46RH. The truck runs and drives pretty well except for a couple of odd issues.
The first issue I noticed is whenever the torque converter locks up the truck experiences what I would describe as "Torque Converter Shutter", but not exactly that issue as it almost seems ignition/fuel related. Gears 1-4 with no lock-up don't experience this but 3-4 when locked up does. I first did the usual tune-up; cap, rotor, plugs, wires. No noticeable difference except for some better pep. The second issue I noticed was idle surging, when cold it would idle between 1000-1300 RPM surging up and down between the two points. Once warmed up it would do the same thing but at a lower idle. I've got a pretty decent hook up at the parts stores and went ahead and replaced my IAC, EGR, TPS. I have an O2 sensor and Coolant Temp Sensor (2 wire for ECM) to put on next.
I also pulled codes before replacing anything, Originally I had codes: 32, 42, 27.
Code 32 has since gone away after replacing the EGR valve (Old EGR had a makeshift block plate put in so that explains code 32) but codes 42 and 27 have remained. I'm aware code 42 is for the ASD, but from my research that usually leads to a non-start scenario. This is where my issue is puzzling since the truck runs great except for when the converter locks up and the slight idle surge. I've also noticed pretty bad gas mileage which would explain code 27 possibly if I had an injector that was dumping fuel.
My current plan is to check the Ohms for all 8 injectors and make sure my splice under the PowerBox looks fine. Also, I'll double-check my fuel pump connector to make sure it is seated all the way.
The previous owner mentioned he replaced the fuel pump and the ECM which fixed the truck from not starting originally.
I'd love to hear some thoughts/conspiracies on this. I picked this truck up to haul material as I work on my first home etc so if worst comes to worst I'll wire the lockup to a switch inside the cabin since at highway speeds the shutter is essentially unnoticeable.
Thanks in advance for any help!

 

I suspect what you are feeling is a miss, not a trans problem. In 4th gear, with tcc locked, the engine has a direct mechanical connection to the driveline, and any performance *irregularities* will be magnified dramatically. On my old truck, I did a tuneup, and had two wires on wrong, the truck drove fine, until it hit lockup in O/D, then it felt like the truck was going to shake itself apart..... turn off O/D, and the problem instantly went away....... Solved my wire issue, and the truck drove a whole lot better.

What spark plugs did you install? IAC? Etc...... These trucks REALLY don't like aftermarket parts in critical locations.... IAC being right up on the top of the list...... O2 sensors should be NTK, or Denso, no Bosch.......

The unstable idle suggests a vacuum leak somewhere. Have you checked your plenum yet? They are notorious for blowing a gasket.... (two-piece intake manifold.)

 

Thanks for the reply, I agree that it doesn't seem transmission related. I used Autolite 3923s as those seem to come highly recommended on this/other forums. The O2 sensor is an NTK, IAC is a BWD, TPS and EGR are WVEs. My idle seemed to smooth out some after replacing the TPS and I swapped back between the WVE and the Holley TPS that I assume is from the factory to confirm the effect. There are a couple of vacuum lines/fittings that don't look great but also don't appear to be leaking just yet. I'll double-check my wires today and am going to the parts store to have codes pulled (hoping this will tell me specifically which injector is causing code 27).
I'll provide an update later today after I've gotten some more information, thanks for the help!

 

The auto parts store probably won't be able to read the codes; a 1994 isn't an OBDII.

You may have to check spark and injectors on each cylinder; easiest is to pull an injector connector and see if it changes how the engine is running.

Or use a stethoscope (also, a long extension or something else solid) to listen to each of the injectors when the engine is running to see if any of them aren't TICKing like the other seven.

RwP

 

Normally this is the case, lucky for me the local store in town rents the full code scanner kits that include the OBDI adapters. But after following HeyYou's advice to check my plenum I can see a decent amount of oil when looking through the throttle body. I've ordered the plenum kit from Hughes and will start with fixing that first before doing anything else. I'll check the injectors at some point before/after the plenum fix but I imagine most of my issue is coming from that. Thanks again for the help everyone!

 

I have a 94 dakota with much the same issue, having trouble resolving. did you get you issue solved?