Help Please

[Igotskills]

I have a 1998 Honda Passport 4x4 3.2 v6. When driving down the highway and maintaining a speed it will start to up shift and down shift for no reason at all. It only seems to happen when I am trying to keep it at a constant speed meaning I am not accelerating or slowing down just trying to stay with the flow of traffic.

That is the first part of it then when I get of the highway and come to a stop it will sometimes stall. The weird thing is it will start right back up. Sometimes it does seem to have a few second delay where the starter will click or it won't do anything for a second while turning the key and then all of a sudden it will turn over and start right up. There seems to be no patteren or consistecy to when it will happen.

About 2 months ago it was doing the same thing but I noticed when I was sitting in park if I would rev it up a few rpms I could not hold it at a steady rpm (Like you would if you were trying to give someone a jump start and you wanted to give it a little extra rpm) it was all over the place. I would barley give it some gas and it would rev up quite a bit and if I took my foot off the gas it would stay there for a few seconds and then start to come down and if I tryed to keep it at say 3000 rpm I could not do it it would just go up to far so I would let off the gas then it would come down to far I could not keep a constant rpm. So I decided to change the Idle Air Control Valve and everything seemed to be fine. I drove it for 2 months with no problems and now it started to do the same thing again except it does not seem to be as bad yet.

I do notice it does not seem to do this until it is good and warmed up say 10 to 15 min after driving. I am not getting a check engine light for codes. I can hear the fuel pump hum at what seems like a louder hum then normal like it is laboring or something. I don't think it has anything to do with the transmission because it seems to shift great but something is making the transmission shift when going down the highway like I described. It almost seems like what ever is causeing it to not be able to keep a constant rpm when giving it gas is the problem. I hope I have giving a good description of the problems but If you need a better explanation or more info I will try to do better. Thanks for all your help in advance.

[Ramblin Fever]

You didn't mention how many miles.

Has all the usual maintenance been done in the last 40-50k miles, i.e. spark plugs?

Original O2 sensors?

Otherwise, it *almost* sounds like a bad intake manifold gasket, but generally codes would be thrown by now, if it's that bad.

[amigo-2k]

I had the same issue of the tranny. I had the tranny fluid flushed and it disappeared. It was either due to low (most likely) or dirty tranny fluid.

as for your idle issue it is most likely due to a faulty intake manifold gasket.