PontiacBonnevilleClub.com

Hi all. I have a 2000 Pontiac Bonneville SLE with the standard 3800 II. I've had this car since February of 2011, when I sold the high mileage 2001 Bonnie. The car has around 140,000 KM's (around 90,000 miles) and ran fine when I bought it (I have probably put on around 2,000 KM's since February...I don't go that far Lol). The last few months, it has had some hesitation at times. At times from a stop, if you give it WOT, it would take a second or two before she started moving. Also, at high speeds (70+ km/h) going up hill, I could feel it slightly hesitate. I have also had to add oil three times to the car since Feb (each time, the oil was low enough to trigger "low oil" light on dash). SES has not been on until today. Car had been sitting for 2 days without use. Left home, and the car was running fine. After a couple mins on highway, I noticed the SES light was flashing. Car was also missing. She held her speed, but I pulled over anyways and looked things over. I didn't see any obvious problems (it was very dark out though), and the wife had to get to work, so I carried on the last few mins...Car ran crappy...Got to wife's work, dropped her off, and scanned for codes. P0300 (Random Misfire Detected). Let the car sit for a couple of mins, then drove the car home. Car seemed kind of OK on the way home, but around half way there, SES started flashing and it started missing again. Giving is gas would just bog it down and make it worse. Got it home, and recorded the Live Date and what not. We also smelt burning oil in the passenger compartment when we had first stopped to check things out. I don't remember spilling any when I last refilled it, but it is possible (this was only a couple of days ago), but I did not see any smoke or anything.

Here is the Freeze Frame Data from the scanner from when the code set:
Freeze Frame Date (When P0300 Occurred)
P0300
Calc Load (%) 19.2
ECT (C) 87
STFT B1 (%) 7.8
LTFT B1 (%) 14.8
MAP (kPa) 90
Eng RPM 1740
Veh Speed (km/h) 101 (Kilometers Per Hour)
MAF (g/s) 32.69
TPS (%) 22.7

Here is the Live Data from when the car was sitting in the driveway after the drive home - SES flashing, engine missing.
Fuel Sys 1 CL
Calc Load (%) 3.9
ECT (C) 92
STFT B1 (%) 0
LTFT B1 (%) -3.1
MAP (kPa) 38
Eng RPM 801
Veh Speed (km/h) 0 (Kilometers Per Hour)
Spark Adv 22
IAT (C) 24
MAF (g/s) 6.70
TPS (%) 0
O2S B1 S1 (V) 0.105
STFT B1 S1 (%) 3.1
O2S B1 S2 (V) 0.875
STFT B1 S2 (%) NA
OBDSup OBS2

I have read so many different causes on this Board, and all over Google, but I couldn't find anything saying what is a "good" and what is a "bad" reading for all the things my scanner read's, so I thought posting this info might help.
If anyone has any idea's, please don't hesitate to suggest it. I am not a mechanic, but thanks to the info on this group, I have learned quite a lot.
Thanks all, and I appreciate any help you can offer.

Wanted to add that when I started it up today, it runs like total garbage at idle, but if I rev it up too 1500+ it doesn't sound too bad.
Any suggestions out there?

Sounds like your PCV is missing an o-ring, or it's otherwise incapacitated.

On the left side of your plenum as you look at it, is the MAP sensor in a cage, it has a wiring connector to it. Unplug the connector and twist the cage so it pops out (Leave the sensor in; I don't remember which way it turns, don't force it). Check that the silver valve in there has an o-ring towards the bottom of the lip and that it rattles, and the o-ring on the cage is fine. If the o-ring is missing or torn, or the PCV is plugged with junk, then replace it. You can get a "PCV kit" at your dealer that comes with the cage, new o-rings and the valve. It's like $25.

Thanks Beast, I'll check it out, and report back. I appreciate it.

That would at least explain your poor idle and oil burning, and could potentially explain the rest of your issues.

Sorry for the delay Beast. I checked the PCV valve. It, as well as the o-ring looked to be in excellent shape. I also bought 3 new ignition coils (seemed easy enough to try), installed them, and there was no difference. I took the coils back, and bought brand new spark plugs (AC Delco Iridium's, GAP set correctly), installed them, and there was also no difference. The car idles terribly, but it "sounds" like it smooths itself out at around 2000 RPM's, but if I hold it at that RPM, the service engine soon light starts to flash because it is still missing (just not nearly as bad). I am going to try and get a new wire set tomorrow, and install that to see if it makes a difference. Do you have any other suggestions? Do you think the readings in my first post look alright?

Thanks again Beast, I really appreciate it.

Well, had the new AC/Delco wires installed. Made no difference. Car still runs like crap, doesn't idle well, and has a strange "knock" or some similar sound coming from down around the harmonic balancer when you give it gas for a quick second (it doesn't make the sound any other time). Once the car is revved up, it runs and sound fine. If it is under load, with the car in gear, and the rear defroster, and the front defroster on, it really bogs itself down and sounds terrible.

Any more ideas from anyone? I have a regular OBD2 code scanner with the 'live data', if that helps. Thanks.

Have you checked for vacuum leaks, both visually and with some carburator cleaner sprayed on the vac lines?

Visually they seem ok, but I'll grab some cleaner and check them out that way too. Thanks again

Vacuum lines all seem ok, no leaks present. I watched a youtube video, and the Bonneville (1995 or so, with the standard 3800 II) was making the same sound my car is, and running just as bad. The owner "thinks" it is the harmonic balancer. If the harmonic balancer is on it's way out, could it cause any/all of these symptoms?