Hi fellas. I drive a 96 Park Ave Ultra, and a few weeks ago the engine light came on for a P0336 code (crank position sensor). The car would occasionally stumble at high speed (RPM would suddenly drop along with noticeable sudden deceleration), but nothing too serious or noticeable. I cleared the trouble code, and it came back a few days later. The stumbles got more serious over the next week, and suddenly the engine cut out suddenly at about 85mph. As soon as I maneuvered over into the breakdown lane, it turned back on just as suddenly. Later on the same drive, the engine cut out completely during braking from 65mph to a stop light.

So, I removed and replaced the crank position sensor, but I have not yet completed a CASE learn (the mechanic across the street says it'* a three hour job since he has to program his snap-on scanner to do it). The car now runs fine at high speed, but at low speed (less than 20mph) or idling it repeatedly stumbles and the "check oil level" light turns on and off (dipstick says level is fine). No trouble codes are set, and it did not behave like this at all before i replaced the sensor.

Does this sound like something that a CASE learn will fix, or is it something more sinister? The oil level light makes me nervous.

Appreciatin' any help.

Notes:
Alternator, throttle position sensor, and wheel hubs replaced within last month.

I don't think the CKP signal being off will effect driving that much when not at wide open throttle, if you are sure nothing was damaged when you installed the new CKP, then I'd find a garage that will do a Crank Learn for you, just ask them if they have a Snap On, Tech II, or similar scan tool, if they have one of those they can do the relearn in 5 minutes.
It takes a minute or less to navigate to where you start the crank learn, then you rev it to a certain RPM, I forget what it says exactly, but after that you just follow the directions on the scan tool, which just takes like 2-3 minutes.
I have never done one, but I cannot imagine what is going to take your neighbor 3 hours to do, if 2hrs & 55 minutes of that time is spent on him updating his scan tool, I cannot see him charging you for 3 hrs work, 1 hrs worth max maybe...

You can expect a garage to charge at least 50.00, a dealership would only charge around 100.00 or so, they would re-flash the whole PCM though, which is really unnecessary in most cases.


As for your oil pressure light coming on and off, but the oil level right, I'd suspect the oil pump starting to fail, I could be wrong there though, I am sure somebody more helpful will respond soon, I mainly wanted to comment on the Crank Learn matter, as I have looked into this before as I changed mine, the car ran fine afterwards, so I never got mine done, eventually I plan to get one, it is on my list for my 96' PA

i would suspect the wiring/connector for the crank sensor more than a relearn. and the level sensor if your pressure is good i wouldnt think the pump is bad, something wrong with the sensor or wiring to that too

Whoops, I read that wrong, I read oil pressure, not oil level, :o
Need coffee!

Unless you experienced this low speed stumble prior to the new CPS, I strongly recommend you get a CASE learn. William is correct in that it only takes around 5 minutes.

Thanks for the replies folks. I don't have access to the car right now as I'm out of town this week, but I left it with a buddy to get the CASE learn performed. A fella I know at O'Reilly did an electrical test that turned up a bad battery, which was replaced (under warranty). I only had a chance to drive it around for a few hours before leaving, but it didn't stumble or anything during that time. The idle was a bit rough, but from what I've read that should be fixed by the learn.
I knew the learn only took a few minutes when I talked to the mechanic across the street, which is why he'll never see me in his shop again.

I'll see what happens after the procedure is done. If all is well, hopefully I'll have the presence of mind to post about if for posterity.

Thanks fellas.

So my buddy brought the car into a Chevy dealership today to have the CASE learn done; but when the tech looked at it, he said that you can't actually do the procedure on a '96, since they don't need it. According to him the procedure can only be performed on '98 and above vehicles. My car has the Series II L67, which I believed was identical to the '97+ except for having the 4T60-E HD tranny.

Any thoughts?

I know for sure the 97'* can get a CASE learn done, the only time I know of that you can avoid it with the 97'* is if you change the PCM, and swap the old knock module over to the new PCM.

I have not gotten a CASE learn done on my 96' PA yet, but I am almost positive it can still be done, I was told by somebody that has flashed a few PCM'* that it can be done, and needs to be done on my 96'

I know this is info I am going to paste here is from a 97', still trying to find info on the 96'.
Below is taken from a post I found on another site..

""Service Manuals for 1997 GTP

The crankshaft position system variation compensating values are stored in the PCM non-volatile memory after a learn procedure has been performed. If the actual crankshaft position variation is no within the crankshaft position system variation compensating values stored in the PCM, DTC P0300 may set (refer to Diagnostic Aids for DTC P0300).

The crankshaft position system variation learn procedure must be performed when replacing the PCM to clear DTC P1336. The crankshaft position system variation learn procedure is also required when the following service procedures have been performed, regardless of whether or not DTC P1336 is set:


PCM replacement.
Engine replacement.
Crankshaft replacement.
Crankshaft balancer replacement.
Crankshaft position sensor replacement.
Any engine repair(*) which disturbs crankshaft/harmonic balancer to crankshaft position sensor relationship"

Get a second opinion. Take it to another dealership.

I called another dealership and they said I should be able to perform the procedure no problem. It'll be done tomorrow morning.

As for the shuddering and oil level light, I think they're actually related to my use of the Torque android app. I noticed today that the car shudders and the oil light flashes for about five seconds, starting exactly when the app connects to the ECU (after connecting to the ELM327). I tested this about five times, and every time the connection was made, the car shuddered and "freaked out" for a moment. After the connection is made, the car runs fine, but if bluetooth fails and it disconnects and reconnects, the car freaks out again. I started using this app right after my CKP replace, which led me to believe it was the CKP causing the problems. I suppose it might be some weird signalling in the Torque app, or it might be something about the particular OBDII/Bluetooth transceiver I purchased. I guess I'll do more troubleshooting.