Well, finally took the car into a place that does a fair amount of Northstar work. I've got head gasket issues and a fair number of oil leaks. Good thing I really like the car and figure I can't buy as nice a used car for what it will cost to fix mine. I will be getting the Northstar Performance ...

"Some circumstantial evidence is very strong, as when you find a trout in the milk." - Henry David Thoreau.

"Daddy, why does the smoke from the car smell so sweet?" - my daughter this morning.

Oil still looks okay. Down on coolant from yesterday. As the idle smoothed out this morning I got massive ...

It is pretty clear to me that something is amiss as far as that start-up misfire goes. It lasts for a bit and then clears itself up - but while doing so the engine clearly stumbles more than I've ever felt in the four years I've been driving it. It flirts with stalling but hasn't done that yet ...

Just to wind this one up. It ended up being a problem in the wiring harness where an oil leak had damaged the wires - something I missed when checking. A Northstar with an oil leak - how shocking.

2005 GXP with just under 95,000 on it. The car has been in the family since it had 3000 miles on it and it has always been one of the "good" ones.

Past few days it has started each day by running rough for the first minute or two after starting, then smoothing out. Last two restarts were ...

I did have a mild heart stoppage when I looked down and my oil guage (which had been fine earlier) was suddenly reading zero.
...
Now when shut off and restarted the needle does its sweep and after a few pit stops the guage started working again... is this the common stepper motor issue or is it ...

With 60k on it, you have plenty of window of useful life out of it.

What would you say is the "best by" date for the GXP/Northstar Bonneville? Wondering how soon I shold think about getting out of having it as my regular driver. Bought that car from my mom who bought it new - so I know its ...

I had the impression that it wasn't and over tough thing to swap. This is the first car I've had in a long time that I don't have a set of shop manuals for.

I do primarily short city driving with a couple highway trips a week so I'm pleased with the 18.3 I am seeing. The highway trips sure help the average. Can anyone own these cars and not "get on it" at least from time to time. Love that part of having a GXP.

If i did get my hands on a PCM - what's up with the necessary programming?

Finally got tired of looking at the service engine soon light and had another round of diagnostics done on the car to track down the HO2 codes that were being set. After the easy stuff was ruled out I am being told the PCM has an internal fault. With the scan tool connected to the car they are ...

Oh I hear you CMNTMXR57, yes, in so many ways what we have now is superior to what we had before - just looking at the power *and* economy we get out of a given displacement then add in the longevity we get out of today's engines.

Since I don't do this for a living or that often I don't have the ...

Replaced read HO2 sensor with Delphi replacement part. MIL was off for about a day and a half. Now I am seeing P0136 again with added appearances by P0137 and P0141.

Had taken the car to my nearby Buick (née Pontiac) dealer for diagnosis - they said they chased it down to the after cat HO2 sensor ...

So Delphi (Delco) over Denso? Sounds like Bosch is out of favor as well?

Paid ex-Pontiac dealer for the diagnostic and will give it a try on my own...I can always take it somewhere if i can't get the thing loose.

Collected a fair number of compliments on condition of the car, which is always nice (now about the rust starting by the fuel filler door, grrr.)

Thanks CMNTMXR57 for the information - I didn't see this until after dropping the car off for service this morning. - so someone running those steps has run up $100.00 for diagnostic so far. The tests confirm a bad sensor which they'll replace for $199.00 on top of the diagnostic fee. Alternate shop ...

sextrosgxp wrote:Yes , there was a service bulletin on it. Im not sure if your car still qualifies, but it is worth checking out.

I'm sure I'll have "just missed it" as that how my luck works...like thinking how well the car has been behaving since I had some front-end work done.

Ouch. Would that be under some kind of emissions warranty? trying to track that down.

Greetings,

I was thinking how nice the car was running and I've not seen the mystery oil pressure drop in weeks...then the SES light comes on. Autoparts store scanner says P0136. I've yet to go under the car to check for any leaks around the exhaust system (but the car doesn't sound any different ...

Bet you saw my earlier posting. I've only had the problem crop up once since winter started - same thing, Oil pressure gauge dropping to zero. I stop and restart engine - viola, oil pressure is back.