Hello everyone,
Here in Cincinnati its been running in the 100 degree range for the past couple days. When I say its hot, I mean my sweat has had sweat.... Anyways recently I was looking through the local Wheeler Dealer and found a Red 1996 Bonneville that looked like it just rolled of the production floor up in Detroit. Turns out it was a single owner and the owner was a elderly lady that recently lost her husband and she felt she couldn't or didn't need the car cause when the car was started and warm it would give the P0300 misfire code. She had always took it took a well known Pontiac/Buick dealership here in Cincinnati and was charging out the wazoo to change parts for her. So I ended up with the car. She has had 1 coil pack changed and was charged like $180.00 to install the new coil pack. Anyways once I got the car I started with:
1. NGK Plug change, and have NO Change.
2. I cleaned the MAF sensor again NO Change.
3. Changed all 3 coil packs again NO Change
4. I inspected and cleaned all electrical connections to ANY sensor NO Change
5. Changed the ICM (Ignition control module) NO Change Although when I changed the ICM it ran good for like 2 days and then the misfire returned.
6. I noticed BLACK Carbon coming for the tail pipe and a smell of Sulfur after starting, so I changed the Catalytic Converter. Still NO Change.
By this point I'm thinking OMG whats the dill with this pickle? I changed everything myself so I know it was done right. So I think what the Hell is left.?
I'll change the Serpentine Belt and think on this some more.. I pulled the motor mount while changing the belt and I thought. Back to GOOGLE and more research to figure this problem out, and noticed more than a couple people talking about the Crankshaft Position Sensor. I figure it is $32.00 bucks and a rent a pulley to pull it. I'll change it and see what happens.
First off I want to tell everyone if you rent a harmonic balancer puller from AUTOZONE the bolts that come with the kit will NOT work to pull your balancer. Bonneville's have M6 size bolts in the harmonic balancer predrilled holes to pull the balancer. SO stop at Home depot and get 3 M6 2 1/2 to 3 inch bolts for the puller. Of course you will need a couple washers for the bolts to connect to the puller itself. I would get at least 3 washers per bolt. .11 cents each.....Anyways once you pull the balancer you will have a black plastic piece to remove after you unplug the Crankshaft Sensor it's just a round black plastic guard for the Crankshaft Position Sensor. Anyways once you get the new Crankshaft Position Sensor in and everything put back together your Bonneville will run like a brand new car!
Point in this seems to never end post,,, is if you're having MISFIRE or STALLING issues and throwing the P0300 code I personally would start with the CRANKSHAFT POSITION SENSOR. By the way this is a completely

Nice. Always good to see a resolution.

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95 SLE... a keeper. 241k miles. Low and Slow.
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Thank you. I was beginning to wonder if I was ever gonna Get the car fixed. Plus I was running out of money just to keep buying parts.
That's why I posted this story I have seen so many stories on the 3800 series 2 motors having a misfire problem I thought well if someone is having this same problem to start there. What I did NOT mention in the story was that I only got 1 Check Engine Light that went away by itsself within 30 mins. NO OTHER CODES showed, hell 99 percent of the time I didn't have a light at all, it just never came on. I could tell there was something not right, but with out a check engine light.... Bonnevilles are an AWESOME car. The ride like a caddy, without the HUGE price tag.