Hey everyone, I'm a recent new owner of my first Dodge product. I have some questions about how the truck runs and I hope you all can help. It may be normal but I just don't know. Its a 1991 Dakota, 4x4, Auto, 120k miles and I've noticed that when I start the truck it turns over great and starts right up and begins to idle great to warm up like its supposed too...however, it doesn't matter if the truck warms for 5mins or 20mins when I put the truck in Drive and hit the accelerator to move forward the initial response is terrible. The truck hesitates and pulls down as it seemingly bucks a little as I move forward. It acts almost as if it wants to stall but I catch it and give it more gas and it comes out of it. It has never stalled from this tho..just feels like it wants too. If I give it more throttle and bring the rpms up it appears to do better. This isn't a huge concern because once I'm on the road and have stopped and started a few times the response seems to get better from a stop. ..not great, just better. Is this something that's expected of these automatic 3.9s with 120k miles or is this an indication of a malfunctioning part?

*While on the road driving normally the truck operates great. It pulls well, responds well, has power, tranny drops down decently to accelerate, moderate pinging every now and then due to crappy gas I'm sure.

- it also bogs down/hesitates with terrible throttle response while in park or nutral when throttle is applied. If I give the truck a decent push of throttle it moves threw that terrible hesitation point and sounds great. When my foot is removed from the pedal it comes back down in rpm just fine and settles out. Then if I hit it again same deal..

Its just something that irritates me, I can live with it if its normal. I hope I gave enough information. Thanks in advance!

**Within the last recent 100miles I have replaced the water pump, coil, all plugs and wires, PCV valve, Cap, rotor and the entire distributor(which came with a new pick-up/hall sensor) I set the timing to vehicle specs at exactly 10*.

 

Off hand, I'd say you have a sensor problem or you installed the distributor improperly. From my recollection, the distributor is set for position, not for idle timing. Have a look at the factory service manual just to make sure.

Have you checked to see what (if any)diagnostic codes are stored on your ecu?

 

Ill check for codes when I get home today and reply back if I find any or not. The original codes when the truck shut down on me was for the hall effect sensor. It was bad and when I replaced it the reluctor plate on the shaft of the distributor was so rusted up that it still faulted. so I then replaced the entire distributor. Ill reply with codes if any within 6hrs. Thanks!

*I did set the timing with a light gun and not by position of the rotor/balancer and timing cover.The truck runs better now than it did before I replaced all these parts. Its the hesitation I mentioned in the original post that bugs me.

 

Alfons, I just checked the codes and I got 12, 11 and 22.

All these codes are from recent work/repairs ive been doing on the truck. Not sure how to clear them on this LA engine.

*12 is "a resent battery disconnection"
*11 is " hall effect sensor signal not recieved"
* 22 is " coolant temperature sensor circuit fault"

I disconnected the battery when I was trouble shooting the truck last week before I repaired the hall effect pickup sensor. I was checking my ground circuits. I replaced the hall effect sensor when the codes first were seen (thats how I knew to replace the pickup). And last, I unplugged the coolant sensor to set the timing with a light like it was suggested to me by a mechanic and a few forum replies on other sites. Im pretty sure these are the old codes from before all my repairs.

 

I messed with the truck this weekend a bit. I reset the computer Friday when I got home and cleared the old codes. Drove it to town which is about 20miles each way at about 60mph on a secondary road. Took the interstate back and ran it about 70mph..opened it up a bit. It was stop and go in town. Truck did great. Topped the fuel off with 93 octane to see if it stopped the pinging when accelerating. It seemed to help a little. When I checked the timing before I left it had changed on me. I reset it with my light to 10*. It had moved to about 7 or 8*. The sluggish takeoff seemed to stop or at least not be as noticeable once I set the timing again. I checked the timing again when I got home and it held that time. Im calling it good. I can deal with it. Thanks for all the help. Ill come here in the future for any other issues!!

 

If you encounter this problem again, I would suggest checking your fuel filter as well. 120k is on the OE filter is cause a little build up. You don't know how the truck was cared for before you got it, replacing the filters and such is great insurance. Then you can narrow it down to fuel lines and or filter at that point. Especially since you already addressed the ignition and timing.

 

I replaced the Fuel filter as well that is on the frame underneath the truck. I had access to a hydraulic floor lift and figured I better do it while I had the opportunity. I had forgot about that one. That was done before I done the "under the hood tune up". Its a brand new one. Thanks for the reply!

 

Hey guys, Ive spent many hours and banged my head many times in this one.. The hesitation never did fully stop as I thought. I noticed this more when I was moving very little like as if I were parallel parking..going back and forth. I researched and researched more everyday. I used a multimeter and tested my TPS and it checked out ok as I read that a bad TPS causes these symptoms. I went back over every repair Ive done in the past and found nothing. I removed the EGR valve last weekend and cleaned it VERY well and ran manual tests on it with a vacuum hand pump and it all passed.. reinstalled it with a new gasket. ..that didnt help either. I then found a section in my Hanes manual on testing the EGR while its installed so I did that yesterday and from what I can tell from the test results it passed those tests as well. What I did next was just on a whim. I pulled the vacuum line off the Transducer(see image attached) that comes from the EGR solenoids and put a plug in that line. I removed all other hoses off the EGR itself(basicly removing it from the circuit) and fired her up. Smoooooooth as sill! Drove it around 30mins in a mix of stop and go and cruising speeds and she ran great. Its still a turd but at least the hesitation at light acceleration went away! I may or may not reinstall a new EGR. Ill keep all the parts for my Virginia Inspection..so glad I resolved this mess. I guess the problem was the damn EGR. ..on to the next issue!