I have a 96 dodge dakota 3.9l 2wd and lately it has a problem starting. It will be fine all day but when its first started it will take 15 to 30 sec to start. Than I'll drive it for the first couple minutes it stumbles and idles rough. I've changed the spark plugs, wires, cap and rotor but still has the problem. Only one time was I driving it down the road and it started to chug like it was out of gas. Fuel Pump?

 

Coolant temp sensor? I'd check this as it's pretty cheap to replace

When the truck starts cold, it uses the coolant temp sensor to make a guess of how much fuel to inject. This is called "open loop" mode as there is no measurement or feedback of the exhaust mixture from the oxygen sensor. If the coolant sensor is bad, it may run too rich or lean (usually rich) as the coolant sensor is giving the computer the wrong information. When the truck has warmed up, it uses the oxygen sensor to adjust the mixture - "closed loop" or feedback mode. However, the oxygen sensor needs time to warm up to work properly that's why it can't be used on a cold start.

Also, if you have done a lot of modifications to the truck - headers, intake manifold, throttle body, you may put the computer out of calibration when it starts. My truck will often pop through the intake or hesitate (lean) at stop when first started. When the O2 sensor starts working it behaves normally. I have looked at many things and taken it to several garages before deciding to live with it. I notice it gets worse in warmer weather.

If it's not this, I'd look at the fuel pump or crank position sensor. You can do a pressure test on the fuel pump to diagnose if the volume or pressure is low. If you have a high mileage truck it may be the case.

 

I changed the coolant temperature sensor about 2 years ago. It reads from my observation fairly accurate. I'll check the pressure though. Wouldn't the crank sensor trigger my check engine light?

 

From what I have been told, sometimes the crank position sensor can do funny things that are temperature dependent. It may or may not throw a code.

Often, the truck will stop running and if it is left to cool will start again. If it is damaged, it may produce erratic symptoms as it heats and cools.

Just something to check.

 

It was the coolant temp sensor the one to to the computer not the gauge. The truck runs alot better now, the casing of the wires had melted the wires were mashed and were grounding out, and the sensor was bad. Im not sure why the wire to the sensor rest against the motor. Thanks for the help.