Accelleration jerking (Bravada)

[beamofsunshyne]

Where to begin.......It is a 98 Olds Bravada, 6 cyl (4.3 or 4.1), with approximately 120,000 miles. The transmission shifts hard (which I'm sure is partly due to needing the transfer case fluid changed- the transmission fluid is full). The main problem is that while accellerating, the vehicle will jerk and when it comes to a stop, it wants to die. Very rarely does it actually die though. This began about a week ago.

The trouble codes are:
P1133: HO2S-11 insufficient switching; ratio is below a determined number
P0122: Throttle postion sensor input is lower than expected
P1404: EGR valve stuck open
P0452: Pressure sensor
P0405: EGR sensor voltage is too low
P1870: Transmission component slipping

Okay....so far I have replaced the throttle postion sensor (which probably did not need to be changed), cleaned the EGR valve with carb cleaner (which was filthy), cleaned the tip of the MAP pressure sensor (not the fuel pressure sensor), and visually inspected the oxygen sensor-it was not grimy which I believe the ratio is too lean; nor was it white. The voltmeter read the MAP sensor at half the voltage that is specified. I read something along the lines that when something fails, the VCM will default to a different operating condition-which explains why the voltage is lower.

I'm not sure what to do next, I'm kind of overwhelmed. Thank you so much for your help!

[Chris Stewart]

Wow, that's a load of trouble isn't it?
Voltage may be a common factor so you may check your battery voltage, it should be around 13.5 volts. You might clean the battery connections too.
You should have around 14 volts with the engine running.
Harboir Freight has an inexpensive digital volt-ohm meter on sale...I paid $2.99 for one....pretty accurate too.
Has the transmission fluid & filter been changed?
The pressure sensor is on the gas tank I think...you might be sure the gas cap is tight.

[old_master]

Always diagnose and repair DTC's in the order they appear on the scan tool. After the repair, clear the DTC's, and complete a drive cycle. If more DTC's show up, repeat the procedure for each DTC as they appear.

The P1133 is a problem with the passenger side oxygen sensor. At 122,000 miles, all 3 oxygen sensors are overdue for replacement. If they haven't been replaced yet, replace them, clear the DTC's and complete a drive cycle. Post your results.

[beamofsunshyne]

Ok, the gas cap is tight, and I replaced the HO2 sensor. The transmission fluid is okay as well. I did have the transfer case fluid changed. The grease in the rear end is okay too. Driving wise......it seems somewhat better and smoother, but it still isn't right. Upon the initial accelleration, I can feel the rear end not catching right....it does this as well every now and then when the gears change. Torque converter? Also, when I came to a stop, the engine sputtered a little like it was going to die...but didnt. The codes say that the voltage is still too low. I checked the wiring plugs/harness at the VCM and they looked fine, not gunky.
Hmmmm?

[old_master]

CORRECTION TO POST #3 : DTC P1133 refers to the oxygen sensor on the DRIVER side "Y" pipe in front of the catalytic converter. The sensors are interchangable left and right. Sorry for the incorrect information.

Disconnect the sensor, ignition to RUN position, engine not running. Check the vehicle harness Pink and Black wires. Pink should show battery voltage, and the black wire should show less than 5 ohms resistance to ground. Post your results.

[beamofsunshyne]

K...changed out the oxygen sensor under the driver side........the only codes showing now are :
P0122 TPS low input
P0405 EGR flow sensor input
P0452 EVAP emission sensor low control

I also changed out the fuel filter.....which was pretty clogged.
The SUV still drives the same.....slightly better.......but not well enough......however....we noticed that when revving the engine and unplugging the harness from the map sensor the engine operates normally....no sputtering or stalling.
Could it be the MAP sensor or something else that sends info to the map sensor?
Thanks

[old_master]

Originally Posted by old_master

Always diagnose and repair DTC's in the order they appear on the scan tool. After the repair, clear the DTC's, and complete a drive cycle. If more DTC's show up, repeat the procedure for each DTC as they appear.

All sensors send data to the ECM, (they do not receive data). When a sensor is disconnected, ie MAP sensor, the ECM applies a substitute value for the sensor based on other sensor inputs. If there is a problem with the MAP sensor, it will set a DTC and illuminate the SES light.


Check voltage at the TPS with the key on, engine off: Gray wire should be approximately 5 volts. Dark blue wire should be less than .25 volts. Turn the ignition off, disconnect the TPS connector. Black wire should be less than 5 ohms to ground in the vehicle harness. Post your results, (don't just replace the TPS).

The P1133 gave you a "set" of DTC's, after you replaced the Oxygen sensor, the P1133 went away. The P0122 has given you a new "set" of DTC's. After it is diagnosed and repaired, clear the DTC's, complete a drive cycle, and continue if the SES light comes on again.