Hi all, lots of detail below.

For the last 4 months, my van has been increasingly getting worse. The sympoms began with mild hesitations when driving 40-50mph. I would be driving and I just kept feeling like the van was "hiccuping". It was subtle, but I noticed it. I noticed it more if I tried to maintain a speed with light pressure on the gas peddle.

Then, when parked, stopped at lights, etc... I began noticing some strange idling going on. The rpms would jump around (between 800 - 2500) erratically, it would feel like the van wanted to die at times, etc...

To date, we have changed out the Throttle Position Sensor, the Coil pack, new spark plugs, spark plug wires, alternator, battery and recently something that has made things better...the EGR Valve.

Before the egr valve, when idling it would get really bad. The car would literally be shaking. Right after putting the egr valve on...it drove like a dream. Smooth, no issues. Then it rained the next day and I noticed when driving, it was ok...but when the van would come to a stop or slow down...the idling would mess around. Not like before the EGR valve, but enough to be annoying. I find the problem gets worse if it rains or is moist/humid.

I also would find if I was driving between 30-50...if I took my foot off the pedal, the van would literally hold its speed for a period of time. I even found this from a dead stop. Just sitting in my driveway with the parking break on...instead of 800RPM's, it would be 1500-1800 and just stay there.

What could be the problem? We have cleaned the throttle body with cleaner.

The very first original thought we had 4 months ago was maybe it was a transmission issue. We had a transmission flush done, but that obviously failed to help. Is there a potential I have a transmission problem? I have no issues driving the van, speeding up to 70 if I have to, etc... it accelerates just fine.

Thoughts?

Thanks

 

Do you have a check engine light on? if so, read the codes and see where that leads you. Also check for vacuum leaks at the throttle body, plenum or intake manifold.

 

I have not gotten any lights at all. We also have checked for vaccum leaks using throttle body cleaner and unable to find anything.

The latest thing we might check out is the Idle Air Control.

 

Did you fixed this problem? I do have exactly same problem with my VAN and I spend too much to replace sparks wires and a few sensors but the problem is still there.