Check engine light eliminates off idle stumble.
 

Continueing saga of my "new" 95 88. I think now the challenge begins. Tranny rebuilt recently. New plugs and a couple tankfulls of injector inhanced fuel. Car starts great, idles great. Now, a gentle take off from a stop would bring up a engine miss, give the throttle just a little more and stumble would go away. Also noticed "stumble" when cruising at highway speeds, again very little throttle (love OD trannys). Figured maybe TPS going south (157k on engine) or TB and MAS needing a good cleaning. This morning CEL comes on and the off idle stumble is gone and I noticed the idle smoothed out. CEL is staying on. "Stumble" at highway cruise gone also. I am gonna ante up and take it in and have the code(s) pulled and see whats up. Thought I would run this by you guys first. I had bought this car for my daughter, she won't drive it 'cause its an "old mans car". I have become enthralled with the power and comfort this thing has and it now has become a "keeper" for the "old man" to drive. I would have not even considered this till I found this site. I find a wealth of information and help here and I am confident I will be able to have this luxo rocket rig running perfect in no time.

Sounds vacuum related. What's the code say?

When I ran into a similar situation, it turned out to be a bad O2 sensor. However, as Dame said, getting the codes will lead us in the right direction.

I have an appointment for Monday to get this checked out. I will post the results of the scan. BTW, CEL went out and the stumble came back. I am going to do a through vacuum line and sensor connector check this weekend, sometimes its a simple thing. :)
I figure I will eventually need to buy the right scan tool since I am going to keep the car. But I will have to sneak that one by the "fiscal dispursement officer" :D Shes real good about understanding ya gotta have the right tools to do the job, plus she drove it for the first time today and came back with a big grin on her face. Her comment, "this thing will actually light a tire off the line and pulls like a horse all the way to redline"!! Thats why I love that women!!! :P

CEL cures stumble....update
 

Had codes pulled today on my '95 88. It had an off idle stumble that would go away when the CEL came on. Codes indicated bad egr "position". $435 fix. I gonna read the tech tips and try cleaning it. If cleaning won't work, will buy a new one ($130-160) and install myself.

I've cleaned this style EGR with carb cleaner and had good success. Worth a try..make sure and operate the pintle with cleaner in it. A new gasket is a must for reassembly.

Off idle stumble fixed.
 

Trouble code P1406, EGR position, came up on scan. Tried cleaning EGR, no luck. Replaced EGR with Borg Warner part (lifetime warranty). $162 @ O'Reillys. 5 minute install. Cleared codes, drove car, all is well. Now, to pull that pesky ABS light bulb. :D

Re: CEL cures stumble....update
 

I'm wondering if the PCM going into closed loop mode being the reason why the off idle stumble goes away when the CEL comes on. Hmm. . . :?: