Here are the engine codes I got from the ECU today:
*Please Note, this is for a 1995 Buick Riviera*

P0113 - IAT sensor high
P0117 - ECT sensor Low
P0137 - OS2 Circut Low Voltage (Bank 1, Sensor 2)
P0138 - OS2 Circut High Voltage (Bank 1, Sensor 2)
P0140 - OS2 Circut No Activity Detected (Bank 1, Sensor 2)
P0341 - Camshaft Position Circut Range/Perf
P0400 - EGR Flow
P0502 - Vec Speed Sensor No Signal

The last one is weird, as my speedo works.

What I'm worried about is P0341, if the sensor is off it can be causing my problems. So do we have a sensor or does it read it off of cylinder 6 like some other GM cars?

The problem I've been having is loss of peformance above about 25% throtle, the engine coughs and shakes the drivetrain.

I would concentrate on the cam sensor and EGR myself. Sorry I don't have the 95 book and wouldn't want to look up a code and have it possibly be wrong.

The O2 just sounds like a bad unit altogether. Definately check out the EGR and the cam sensor. The EGR may be as easy as just taking it off and cleaning it of it'* carbon. The IAT sensor... that'* a little weird but who knows. What does ECT stand for?

ECT stands for Engine Coolant Temp

That'* where I'm starting.
The codes it spit out were standard GM OBDII for the L67. I foud a sheet online:
service.gm.com/gmspo/mode6/pdf/1997/97c381_CGHyE.pdf
I also have a Hayes manual which conferms what that sheet says.

In that case.. search in the techinfo area for codes and use the troubleshooting codes as you already found via that link.

How could I eliminate the cam sensor error, without tearing into the timing chain cover if possable?
Is the procedure the same as '92 L67'*? I found something on that where someone was getting an error code 41 from an OBDI computer.

From the 95 FSM:

P0341 Will Set When
Ratio of fuel control pulses to cam pulses does not equal 6:1.
Above condition for 10 occurences during key cycle.

According to the FSM, basically if the camshaft position sensor circuits 630, 633, 644 or 645 or a faulty Cam sensor can cause the PCM to reinitialize injector sequence causing stumbling or missing. Circuits 573 644 or 645 on the Crankshaft Position sensor, the 18X portion of the crankshaft position sensor or damage vanes on the harmonic balancer can cause the PCM to stop pulsing the injectors.

Looking at the diagnostic section, you want to check your harmonic balancer, and crank and cam position sensors. If they check out alright, it mentions checking to make sure the PCM is ok.


Hope that helps you or the gearheads diagnose!


Regarding those O2 codes, I'd check the sensor and make sure its alright. Looking at those it could just be a FUBAR sensor.

You may want to make sure all the connections are good on your PCM. Did all these codes show up at once? The FSM is saying check PCM as a last resort for these codes.

"Stumbling or missing" is exactically what I have.

I just checked the codes because of the stumbling. We cleared the codes via the reader and I even disconnected the negative terminal and they came back.

How do I check the harmonic balancer, crank, and cam position sensors? Sorry but this is the first time I've done anything like this.

I'd wait on one of the gearheads on this one. I'm just reading from a book here.

While we're waiting though, you might want to pull your O2 sensor and check on it. This conjecture, but if you're running lean from the injector sequence getting reset, you could be generating alot of extra heat and may have cooked your O2. Again this is all guesswork here. Wait for the pros.