nos4rot2

I have had the stumble deamon for about a year and a half, I had about 42k miles on the car then and now I have 55k. I have changed the Ignition control module and coil also done the mod to bring the temperture down on the coil bracket, nothing changed. I changed the plugs and plug wires, nothing changed. I have checked for vacume leaks, and found none, checked the cats to see if they were stopped up and they were not. Scanned for codes and there were none.
I have noticed that the car runs great in open loop but as soon as the car starts to warm up (about 140 deg) it starts to stumble almost like someone is putting their hand over the throttle body opening and choking the air off. This happens from 0 rpm to about 2300 rpm. Idle is smooth and reving the engine in neutral is smooth but any load on the engine up to 2300 rpm is rough. WOT it is not noticable at all and It runs like it should.
I have noticed that in cold weather it is a lot smoother if at all noticable until I stop at a redlight or shut the engine off for a couple of min. then it returns. Summer time is real bad like a bucking horse.
Well I got an autoxray scanner and hooked it up the first thing I noticed is that the instant it goes to closed loop it starts to stumble. I also ran a capture mode so here is some of the data.

Fuel System 1 = closed loop
Fuel System 2 = closed loop
Load Value = 11.3%
Coolant Temp = 208 deg. F
Short Term Fuel Trim 1 = 0.0%
Long Term Fuel Trim 1 = -6.3%
Short Term Fuel Trim 2 = 0.8%
Long Term Fuel Trim 2 = -3.2%
Map Sensor =17 in.hg
Engine RPM = 1854 RPM
Vehicle Speed = 58 MPH
Ignition Timing Adv. = 44.0 deg.
Intake Air Temp = 60 deg.
Air Flow Rate = 3.62 lb/min.
Throttle Posn. = 13%
Oxygen Sensor 1 Bank 1 = 0.760v
Oxygen Sensor 2 Bank 1 = 0.725v

The reason I posted this is so maybe someone will see something I dont. I apologies for the long post but I am bound and determined fix this. Any input is welcome. Thanks.

Rpm280

Not sure, but if it happens when it goes into closed loop it could be the O2 sensors being bad or having some kind of short , Or some other system that has some control of closed loop operation.

nos4rot2

Yea It runs great until it goes into closed loop then it starts. I am going to order some o2 sensors here pretty soon I will see if it does any good.

Fatdog

Maybe just for kicks,might spray some cat approved carb cleaner ever so gently on the little wire in the mas(I think that's what it's called on 94's and up)It's the thing between the aircleaner and the throttle body.Also,disconnect the negative wire on the battery for a couple of hours or so,then reconnect it,then drive the car about 20 miles or so,but gently,so the computer can re learn some stuff.Maybe the computer needs to be reprogramed.My02

nos4rot2

Well the service engine light came on today and here is what it scanned as.

P0410 Secondary Air Injection system malfunction
P0300 Random/ Multiple Cylinder Misfire Detected

Is the misfire code the one that people get when it usually turns out to be the opti?

and also is there a connection between the two as to why I would get the codes at the same time? Thanks...