The car had a slight miss. Too cold of plugs. Put some tr55's in it and changed teh IAC motor. Car ran good. Now when the car warms up and i press the gas more than 1/3 way down after the converter locks up, the car willl bog and shake bad. It runs fine at WOT and idles good. And it doesn't shake or bog when i press the throttle a little bit to accelerate. It also "bogs" with the car in neutral sitting still.

It almost acts like a TPS problem but if it was TPS the car would hesitate to increase RPM's even with light throttle pressure.

Do you think this is 02 related? or something else?


thanks guys

 

I had this problem with my truck and it turned out to be the Crankshaft Position Sensor. It would shake loose during mid RPMs. Ran fine at light throttle and full throttle. Maybe that could be happening with your car? Also, if you have access to a lab scobe try testing the tps and crank sensor.

 

if i got it scanned by Gm would that tell me what sensor if any were bad?

 

update: I unplugged the driver front 02. Car ran better and did not stutter. Now would you draw the conclusion that the culprit is that one 02? or go ahead and replace both?

 

I would just replace both.. might as well. they are not THAT expensive

 

Replace the plug wires and check the coil wire closely.

 

You can narrow down which O2 if you swap them from driver side to passenger side, but you need a scanner to see if the bad readings/codes follow the O2. Else, are these original O2s...might as well, just change both.

 

if your going to get 02's buy both. If one is bad i would think the other isnt going to be far behind it.

If you are going to just buy one make sure it is the same brand as the othe rone you have

FYI Bocsh 02's are crap

 

still doing it with 02 unplugged. Car only does it when warm.

Would a bad alternator cause this problem?

 

try unplugging the mass air sensor and also check for vacume leaks / air getting in the engine after the massair sensor

 

snapping the throttle and bogging down has nothing to do with ox sensors.

check the tps, maf, connectors to each, if they're fine then check the MAP and vac lines.

the control for fuel to the engine is covered by the pcm. pcm reads for instant fuel needs the TPS, map, maf, iat, and iac motor. if maf is bad it will default to speed density and use tps, map and iat sensors.

THIS HAS NOTHING TO DO WITH OX SENSORS. the reason you get no bogging when you unplug the sensors is because it's flooding the engine with fuel...not because those sensors are bad...

 

That's what I was thinking...check the elbow to TB connection...

 

Ok here's some more info.

The car will shake really bad when throttle is pressed about 1/2 way. It only does this in OD right after the converter locks up. Mine locks up around 40mph.) It's not RPM related or Speed related because I can back off on the throttle to just a little pressure but still enough to accelerate. The shaking also clears up after the RPMs climb up a bit.

All this only happens when the car is hot. Does not happen when i crank the car up and leave to work in the morning.

Thanks guys. I'm taking the car to GM dealer today to get scanned and see what the hell is wrong.

 

the shudder is normal for GM transmissions. they have a 'special programming' for the torque converter to be halfway locked for fuel effeciency. it's a retarded programming and any tuner can take it out.

what happens is the converter says unlock but the computer tells it no because you havent opened the throttle enough for the converter to completely unlock. it keeps going back and forth, for lower rpm and better economy....retarded isnt it...??

now, if it's more than a shudder, you may have converter problems, misfire problems, or fuel problems. i dont know how 'bad' you mean when you say bad, and i'd have to diagnose myself.

 

never had a shutter in my car...

Sounds like a heat soaked ICM to me. Try spacing it away from the heads a little and see if that helps the problem.