Hey guys I am about at the end of my rope here and I am hoping you all can help here.

My truck just died on me today on the way to work as I was coasting through the parking lot. It started up again but now I am getting worried that I cant move at the end of this month as this truck is my only means of transport.

Basically, this all started when I replaced the crank case breather filter. I noticed the that cruise didnt work all the time. I thought it was vacuum related but there is strong suction at the PCV valve and crankcase breather ports. I checked all other hoses, connections and I didnt see any sign of wear on any of them, and they are all secure. I have been getting steadly worse gas mileage this last month, I just filled up the other day and I am getting about 11 to 12 now. I have also noticed what sounds like an exhaust leak but I crawled underneath last night with a trouble light and can not find any sign of leaks anywhere in the exhaust.

I have a '93 with 318 and 4 speed automatic. ANY help would be very much appreciated. I dont want to trade in this truck.

 

The breather shouldnt have anything to do with the problem. The exhaust leak sound could be a clogged cat. Are your plugs/wires/pick up recent?

 

Have you replaced the MAP sensor and IAC valve?

 

also check the vehicle speed sensor. does the truck sometimes not shift into OD and stall if you stop too fast? do you notice if the daytime running lights turn on when you start to move or not? also take a look at the splice under the power distribution centre. if its corroded, clean it and re-attach the wires

 

Thank you so much for the quick replies!!!

ChickWithTheTruck,
I gutted the cat last summer. I just replaced the cap, rotor, wires all to mopar performance within the last year. Plugs, I just replaced last month. I am not sure what you mean by pickup.


95 318SLT,
I have not replaced the MAP or IAC valves, could you elaborate on this?



3.9l93dakota,
I just replaced the speed sensor 3 or 4 weeks ago. The lights are not turning on their own. Could you direct me towards the power distribution centre splice? I am not familiar with this. But could easily enough clean a harness.

 

The IAC- Idle Air Control Valve is the device that controls the amount of air that is let into the throttle body when you remove your foot from the gas pedal. I just recently had to replace mine because the truck kept stalling when I dissengaged the clutch. These are prone to going bad on the engines from what I've heard and will eventually stick in one position and not move. The truck will idle, but it will have a hard finding idle after having a load on the engine.

The MAP- Manifold Absolute Pressure sensor. It is similar in function to a mass air flow sensor, but because our trucks have a plenum style intake, they need a MAP sensor, instead of a mass airflow sensor. If this sensor is bad, the computer cannot calculate the air flow coming into the engine, which it needs to know because its one of the factors for computing the amount of fuel that needs to be injected.

 

if the daytime running lights arent turning on, then chances are is you just got a bad sensor. its electronics so this happens all the time. or you could also check the wires on the sensor to see if they are corroded and not connecting properly.

as for the power distribution center (PDC) splice, you have to remove the PDC from the inner fender, take off the tape around the wires directly beneath where the PDC was, and you should see the splice. But read this more here >> https://dodgeforum.com/forum/1st-gen...ont-start.html

 

The truck will turn over and start just fine. But, on our trucks when you start the truck there is a small amount of fuel injected to help it start. Once the truck comes down out of that initial "choke" fuel it will bob around a little on the tach like its gonna die but then come out of it. I only hear that exhaust leak noise when I put the truck in gear, its warm and its at rest. I dont hear it any other time while driving, or while its in nuetral or in park and at rest.

Let me ask something else. If this problem is related to one of the air sensors, would it just be affecting the cruise control? to where I would not notice any problems when I take manual control over the throttle?

 

im gunna go with 95_318SLT's suggestion of the IAC. it sounds alot like the engine is starving for air at initial start up. however, this would not affect your cruise i dont think.

 

Your cruise control not working is most likely the speed sensor that 3.9l93dakota was mentioning, but that speed sensor would not cause the engine to stall. And exhaust leak also would not cause the engine to stall. Like I said before, exhaust leaks usually can only be heard at a specific RPM, it has to do with resonant frequencies. In your case, its the RPM the engine is at at idle while under load and warm.

That bobbing you describe sounds like either the IAC or something wrong with the fuel system. Have you checked your fuel pump, filter, or injectors? Either way you should start by checking the IAC, its very easy to replace and not too expensive.