Yesterday i went to help my brother mve some stuff and i noticed first off that from stop to start it would hesitate and then it would pick back up and go and also my trans wouldn't shift into overdrive anyway i got it home put my truck in park opened the hood and give it gas by hand and with me watching it would hesitate then idle up and when i would release it it would just drop down and cut off it cranks up good no gas and good idle but again i give it gas it hesitates and then i let off it shuts off any help would be greatly appreciated. oh yrha 99 dakota 2wd auto v6

 

Mine does this when I rev it in park or in neutral.. I have to give it gas to keep it alive until it can find itself again.. if I just rev it up and take my foot off, it will almost die out until I give it more gas. I'm also interested in hearing what the problem might be.

 

I had a similar problem, my cat converter was clogged also had an issue with the o2 also replaced. This also helped with gas millage

 

Clean the throttle body. Look down into the barrel of the TB....open the butterfly...if its black with carb, it needs to be cleaned. Get some TB cleaner from your friendly neighborhood parts store, and go to town. Would be a good time to clean the TPS and IAC as well.

 

mine will stall after you rev it in neutral or park also. i think im going to take off the TB next weekend and clean it up, i'll let everyone know how it turns out.

 

its not the bla bla bla clean ur IAC, if that doesnt work check for vac leaks, a cat and a dirty tb wont cause bad idle...clogged IAC yea..

 

um yea it will, you should know that. wait till the TB on your 4.7 gets dirty and see how it idles.

 

uhhh.....blah blah blah are you sure about that????? My idle sure seemed to blah blah level out after i cleaned mine up. Blah blah, but maybe your right. Idle has NOTHING to do with TB. Blah blah

 

Ok........lets go to class.........

Dirty Throttle Body-
Probably the most common problem that causes idle problems in multiport fuel injected engines is a carboned-up throttle body. The symptoms include stalling when coming to a stop, or very low idle after starting, or stalling if the throttle is "blipped" (opened and closed quickly).

(pay attention now...)

When the engine is shut off, crankcase vapors enter through the PCV system and work their way into the intake system towards the air box. The vapors carry with them oil and soot which comes to rest on the ducts and throttle plate. When the engine is started again, the incoming air carries this oil and soot back to the throttle body and are deposited just behind the throttle plate because of the sudden drop in air pressure behind the plate. This build-up eventually blocks off the gap between the throttle plate and throttle body bore, causing less air flow while the throttle plate is closed. Over time, the computer compensates by opening the AIS valve further to bypass more air. The problem is that it gets harder for the computer to control the idle, especially when coming to a stop or when the throttle is "blipped". This build-up also occurs in the AIS passage as well and eventually the AIS cannot bypass enough air to keep the engine idling.

Dude- clean your TPS and your TB.

 

Rough idles 2nd most common cause: Speed/Distance Sensor Failure
The symptoms for this are usually stalling when coming to a stop. This condition is often associated with a fault code, but the sensor can become intermittent and cause idle problems without triggering the fault code. The computer uses the speed/distance sensor to determine the vehicle's speed. As you decelerate, the computer closes the AIS bypass. As the vehicle comes to a stop, it opens it again to maintain the idle speed. This is especially important for vehicles equipped with an automatic transmission because the transmission loads the engine while in gear. Without valid data from the sensor, the ECU does not know when the vehicle is stopping and often cannot open the AIS bypass fast enough to keep the engine from stalling. The only way to solve the problem is to replace the sensor. Be sure to check the wiring first, though. Occasionally, the connector on the sensor itself gets oily and comes loose.