Idling Problems with 89 Dakota

[Gizmokid2005]

I have run out of ideas and need help.

'89 Dakota 4x4
3.9L TBI
AT
120,200

Since about April 4 I have had problems with the idle in my truck. Every time I come to a stop or slow down (below the regular idle speed for that gear) it idles at about 100RPM, or it dies. Sometimes if I wait long enough the idle will recover back to normal. From June until mid-August I never had any problems, it was fine. Ever since then the problems have been ongoing.

I have replaced:
ISCA
TPS
Ignition Coil, Spark Plugs, Wires, Distributor Cap, Rotor.
Water Pump
Belts
Computer

I have checked the timing chain, and the timing itself.

I have 3 possible problems and would like input: 1) Air pump, 2)O2 Sensor, 3)Vacuum/air leaks.

Any ideas?

[Gizmokid2005]

I replaced the computer yesterday to no avail. It still idles wrong, but runs better overall.

[BleedDodge]

Why didn't you replace the idle air control valve yet? I bet you that's all that is wrong here, and it sounds like you've spent hundreds of dollars already...

[Gizmokid2005]

My truck doens't have one.

[BleedDodge]

You said EFI. It must have one.

Maybe you mean TBI?

[Gizmokid2005]

Yeah, that's it.

Sorry i've been out of it a little bit.

[BleedDodge]

So which one is it? Get it figured out yet or what?

[Gizmokid2005]

It's TBI.

Sorry about that.

[BamaDodgenMX]

I don't think you should worry about your O2 sensor. I have the same prob with my 88 D100 w/ rebuilt 3.9 So far I've replaced the TB (used), computer, O2 sensor, Vehicle Speed Sensor in tranny, as well as what youve put on. Anybody have any ideas?

[kellydm]

I had the exact same problem with my 94 Dakota with about the same miles. It was a crack in a vacuum canister. The dealership fixed it so I don't know exactly what part it was.

[Gizmokid2005]

If there is any way you could find out, would you? You have no idea what it would mean to me.

UPDATE: I checked my tranny fluid and added a full Quart to it and I didn't have any problems for a while but now I am low on fluid again and I am having the same problems. But I have no other ideas.

[kellydm]

The only thing my receipt shows is the following:
FP Number: 55035902
Description: Resevoir 14067001
Price: $7.50

Hope this helps!

[Gizmokid2005]

I'll see what I can dig up.

Thanks!!

[stanbell]

I had the same problem after installing a new egr valve. When i stoped at stop signs the rpm's droped dangerously low. to the point of power loss to everything, steering brakes, all of it. I took it to a dealer to have a diagnostic and talk with " an expert". know one could help. So I put the old egr valve back in and solved my problem. The new egr valve was defective and proved to be the problem.

[Gizmokid2005]

Thanks. My main problem was the front pump in my transmission was fried, and spun a bushing. So my tranny was pretty worthless. After I got that back in I changed my EGR valve, and now it runs like new.

Thanks everyone for all of your help and ideas.