HELP! Service engine soon light blink, runs rough, bad smell
-
polo
- SLE Member

- Posts: 46
- Joined: Fri Nov 08, 2019 9:49 pm
- Year and Trim: 2002 Pontiac Bonneville SSEi
HELP! Service engine soon light blink, runs rough, bad smell
So today I went out and started my car...
It idled extremely rough, I stared backing it out gently and then I immediately stopped - then after a few seconds the service engine soon light came on and then started blinking - and then this really bad smell (almost like burning rubber) started.
Turned the car off immediately - then noticed a light yellow colored, sort of what looked like powder (?) or something, on the pavement where the car was.
HELP!
It idled extremely rough, I stared backing it out gently and then I immediately stopped - then after a few seconds the service engine soon light came on and then started blinking - and then this really bad smell (almost like burning rubber) started.
Turned the car off immediately - then noticed a light yellow colored, sort of what looked like powder (?) or something, on the pavement where the car was.
HELP!
2002 SSEi
- AJT2004
- Posts like an LG3

- Posts: 341
- Joined: Tue Oct 19, 2010 7:45 am
- Year and Trim: 2004 Bonneville SE
- Location: New York
Re: HELP! Service engine soon light blink, runs rough, bad s
A blinking MIL is usually a misfire, could be a simple as a disconnected ignition wire on the exhaust manifold.
Did you open the hood for an inspection?
How many miles?
Is maintenance up to date?
Did you open the hood for an inspection?
How many miles?
Is maintenance up to date?
2004 Bonneville SE 151,xxx- 20% tint all around, 5% tint bar on windshield | 4500k DDM HID low | De-badged | Hardwired Passport 9500ix | FWI(inter-cooler piping) | FE2 Rear Sway Bar | Solid Motor Mount | 180* Stat | Firm Shift Kit
- '92 Bonneville SE - '85 Grand Am - '73 Catalina - '67 Catalina
- '87 Bonneville SE - '82 6000 - '78 Catalina [/color]
- '92 Bonneville SE - '85 Grand Am - '73 Catalina - '67 Catalina
- '87 Bonneville SE - '82 6000 - '78 Catalina [/color]
-
polo
- SLE Member

- Posts: 46
- Joined: Fri Nov 08, 2019 9:49 pm
- Year and Trim: 2002 Pontiac Bonneville SSEi
Re: HELP! Service engine soon light blink, runs rough, bad s
Opened the hood after I turned the car off... checked the coolant level and color, transmission fluid color, oil color... all OK.AJT2004 wrote:A blinking MIL is usually a misfire, could be a simple as a disconnected ignition wire on the exhaust manifold.
Did you open the hood for an inspection?
How many miles?
Is maintenance up to date?
Just turned over the 100,000 mile mark.
Yes, maintenance is up to date - the car is very well taken care of.
However, I got to thinking...
In the last few weeks, after I filled up with gas from a gas station I never used before (still Shell) - the car, twice, when I turned it on had a slight rough idle - but when I backed out of the driveway and began to drive, after a block or two it went away and ran normal.
I chalked it up to "bad gas" from the new gas station I went to.
However, looking back on it - it only happened AFTER if rained... both times...
So, something with moisture getting in somewhere? Maybe...?
2002 SSEi
- AJT2004
- Posts like an LG3

- Posts: 341
- Joined: Tue Oct 19, 2010 7:45 am
- Year and Trim: 2004 Bonneville SE
- Location: New York
Re: HELP! Service engine soon light blink, runs rough, bad s
Ignition wires are suspect, if they're original or over 5 years old replace. I recommend using OEM quality- Delco, Delphi or Denso. Funny all begin with D!
You can check at night using a spray bottle filled with water. Carefully spray the wires, if you see any sparking consider that your smoking (sparking) gun.
You can check at night using a spray bottle filled with water. Carefully spray the wires, if you see any sparking consider that your smoking (sparking) gun.
2004 Bonneville SE 151,xxx- 20% tint all around, 5% tint bar on windshield | 4500k DDM HID low | De-badged | Hardwired Passport 9500ix | FWI(inter-cooler piping) | FE2 Rear Sway Bar | Solid Motor Mount | 180* Stat | Firm Shift Kit
- '92 Bonneville SE - '85 Grand Am - '73 Catalina - '67 Catalina
- '87 Bonneville SE - '82 6000 - '78 Catalina [/color]
- '92 Bonneville SE - '85 Grand Am - '73 Catalina - '67 Catalina
- '87 Bonneville SE - '82 6000 - '78 Catalina [/color]
-
camopaint0707
- SE Member

- Posts: 21
- Joined: Mon Dec 20, 2021 10:04 am
- Year and Trim: 02 ssei
Re: HELP! Service engine soon light blink, runs rough, bad s
flashing engine light means misfire. I wouldn't drive it until you get that squared away.
-
polo
- SLE Member

- Posts: 46
- Joined: Fri Nov 08, 2019 9:49 pm
- Year and Trim: 2002 Pontiac Bonneville SSEi
Re: HELP! Service engine soon light blink, runs rough, bad s
Well, brought it into the dealership...
Got a message saying it has a bad O2 sensor and the third cylinder is misfiring...
Bad... ?
Got a message saying it has a bad O2 sensor and the third cylinder is misfiring...
Bad... ?
2002 SSEi
- 95naSTA
- Certified Bonneville Nut

- Posts: 7087
- Joined: Wed May 21, 2008 11:47 pm
- Year and Trim: 95 SLE
- Location: Philadelphia
- Contact:
Re: HELP! Service engine soon light blink, runs rough, bad s
Are they doing the repair?
What are you asking is bad? These issues are relatively straightforward.
What are you asking is bad? These issues are relatively straightforward.

95 SLE... a keeper. 241k miles. Low and Slow.
97 BMW 528i
98 Infiniti vq35'd i30: 13.3@104mph, 30MPG Hwy (RIP)
02 Jag X-type
03 BMW M5
05 Chevy Cobalt LS
07 Infiniti G35s 6MT (Sold)
07 Ducati Monster S2R 800 with DS1000 swap
83 Yamaha IT175K
72 Yamaha DS7: '74 RD250 swap, JL chambers
Info on dropping a 92-99: Here.
-
polo
- SLE Member

- Posts: 46
- Joined: Fri Nov 08, 2019 9:49 pm
- Year and Trim: 2002 Pontiac Bonneville SSEi
Re: HELP! Service engine soon light blink, runs rough, bad s
Yes, they will be repairing it...95naSTA wrote:Are they doing the repair?
What are you asking is bad? These issues are relatively straightforward.
Bad as in... a lot of money...?
Haven't been able to get a hold of my "service advisor" today yet...
2002 SSEi
- 95naSTA
- Certified Bonneville Nut

- Posts: 7087
- Joined: Wed May 21, 2008 11:47 pm
- Year and Trim: 95 SLE
- Location: Philadelphia
- Contact:
Re: HELP! Service engine soon light blink, runs rough, bad s
Since it's the dealership it'll be more expensive than elsewhere but you're probably looking at $150-200 in parts and 3-4 hours of labor to include diagnosing.

95 SLE... a keeper. 241k miles. Low and Slow.
97 BMW 528i
98 Infiniti vq35'd i30: 13.3@104mph, 30MPG Hwy (RIP)
02 Jag X-type
03 BMW M5
05 Chevy Cobalt LS
07 Infiniti G35s 6MT (Sold)
07 Ducati Monster S2R 800 with DS1000 swap
83 Yamaha IT175K
72 Yamaha DS7: '74 RD250 swap, JL chambers
Info on dropping a 92-99: Here.
-
polo
- SLE Member

- Posts: 46
- Joined: Fri Nov 08, 2019 9:49 pm
- Year and Trim: 2002 Pontiac Bonneville SSEi
Re: HELP! Service engine soon light blink, runs rough, bad s
Well, it wound up needing a new O2 sensor and coil.
Thanks for everyone's help as usual!
Thanks for everyone's help as usual!
2002 SSEi
-
polo
- SLE Member

- Posts: 46
- Joined: Fri Nov 08, 2019 9:49 pm
- Year and Trim: 2002 Pontiac Bonneville SSEi
Re: HELP! Service engine soon light blink, runs rough, bad s
Well...
Dealership says they can't get the O2 sensor off without stripping it...?
And if they do that I would need a new catalytic converter...
So I should just drive around with the SERVICE ENGINE SOON warning light on.
Classy...
Dealership says they can't get the O2 sensor off without stripping it...?
And if they do that I would need a new catalytic converter...
So I should just drive around with the SERVICE ENGINE SOON warning light on.
Classy...
2002 SSEi
- luke_dubs
- GXP Member

- Posts: 254
- Joined: Wed Jun 25, 2014 8:14 pm
- Year and Trim: 2013 Regal GS
- Location: OH
Re: HELP! Service engine soon light blink, runs rough, bad s
Find a shop that can actually replace an O2 sensor without charging you a stupid amount of money for it.
When I helped my uncle get an O2 sensor off his Cruze (different vehicle, I know), we used one of those small blowtorches to heat up the threads, and it came off, rather forcefully. It's much better than trying to take it off of cold pipes.
When I helped my uncle get an O2 sensor off his Cruze (different vehicle, I know), we used one of those small blowtorches to heat up the threads, and it came off, rather forcefully. It's much better than trying to take it off of cold pipes.

'02 Pontiac Bonneville SE 108,539 miles, N/A, SSEi exhaust system, boat roller mount. Gone, but not forgotten.
'13 Buick Regal GS 122k miles, 270 hp, 295 lb/ft, ZZP intake.
(yes, there is a story behind my avatar.)
- 95naSTA
- Certified Bonneville Nut

- Posts: 7087
- Joined: Wed May 21, 2008 11:47 pm
- Year and Trim: 95 SLE
- Location: Philadelphia
- Contact:
Re: HELP! Service engine soon light blink, runs rough, bad s
Find a muffler shop. If they can't get it out with a torch they can drill it out and weld in a new bung.

95 SLE... a keeper. 241k miles. Low and Slow.
97 BMW 528i
98 Infiniti vq35'd i30: 13.3@104mph, 30MPG Hwy (RIP)
02 Jag X-type
03 BMW M5
05 Chevy Cobalt LS
07 Infiniti G35s 6MT (Sold)
07 Ducati Monster S2R 800 with DS1000 swap
83 Yamaha IT175K
72 Yamaha DS7: '74 RD250 swap, JL chambers
Info on dropping a 92-99: Here.
-
dougtoth
- Posts like an LN3

- Posts: 434
- Joined: Thu Mar 31, 2011 8:57 pm
- Year and Trim: 2005SLE CRIMSON
2005SLE PEARL
1975 MONTE CARLO - Location: MUSKEGO,WISCONSIN
Re: HELP! Service engine soon light blink, runs rough, bad s
When we did the one on my 2000SLE we used a torch to heat it up cherry red hot.
It then came out rather easy.
We then used a tap to chase the threads before we put the new one in. (TAP 18-1 5MM PLUG)
Use the anti seize on the threads on the new one.
Only on threads not on the sensor itself!!!!
It then came out rather easy.
We then used a tap to chase the threads before we put the new one in. (TAP 18-1 5MM PLUG)
Use the anti seize on the threads on the new one.
Only on threads not on the sensor itself!!!!
- harofreak00
- Administrator

- Posts: 26022
- Joined: Mon May 19, 2008 6:04 pm
- Year and Trim: 2004 GXP - plus a handful of other Bonnevilles
- Location: Browerville, MN
- Contact:
Re: HELP! Service engine soon light blink, runs rough, bad s
polo wrote:Dealership says they can't get the O2 sensor off without stripping it...?
And if they do that I would need a new catalytic converter...
...and most people believe this crap? From a dealership? I'd never set foot in there again if they are trying to pull that.
Andrew - owner/operator of Bonnevilles Unlimited

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 57k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 115k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 280k | Official Bonneville Hauler

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 57k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 115k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 280k | Official Bonneville Hauler
-
polo
- SLE Member

- Posts: 46
- Joined: Fri Nov 08, 2019 9:49 pm
- Year and Trim: 2002 Pontiac Bonneville SSEi
Re: HELP! Service engine soon light blink, runs rough, bad s
Well, won't be able to get the O2 sensor fixed until after Christmas now...
What are the "affects/effects" of a bad O2 censor...?
Bad gas mileage? Low power? Bad smell? Anything major that would harm anything...?
What are the "affects/effects" of a bad O2 censor...?
Bad gas mileage? Low power? Bad smell? Anything major that would harm anything...?
2002 SSEi
- AJT2004
- Posts like an LG3

- Posts: 341
- Joined: Tue Oct 19, 2010 7:45 am
- Year and Trim: 2004 Bonneville SE
- Location: New York
Re: HELP! Service engine soon light blink, runs rough, bad s
The critical item is the misfire, was that resolved? After that is repaired, clear the code(s) wait to see if the MIL stays off.
Do you have a code reader/scan tool?
Separately, I would suggest bringing the car to a recommended repair shop if further work is needed.
Do you have a code reader/scan tool?
Separately, I would suggest bringing the car to a recommended repair shop if further work is needed.
2004 Bonneville SE 151,xxx- 20% tint all around, 5% tint bar on windshield | 4500k DDM HID low | De-badged | Hardwired Passport 9500ix | FWI(inter-cooler piping) | FE2 Rear Sway Bar | Solid Motor Mount | 180* Stat | Firm Shift Kit
- '92 Bonneville SE - '85 Grand Am - '73 Catalina - '67 Catalina
- '87 Bonneville SE - '82 6000 - '78 Catalina [/color]
- '92 Bonneville SE - '85 Grand Am - '73 Catalina - '67 Catalina
- '87 Bonneville SE - '82 6000 - '78 Catalina [/color]
-
polo
- SLE Member

- Posts: 46
- Joined: Fri Nov 08, 2019 9:49 pm
- Year and Trim: 2002 Pontiac Bonneville SSEi
Re: HELP! Service engine soon light blink, runs rough, bad s
Yes, the misfire was fixed - it needed a new coil.AJT2004 wrote:The critical item is the misfire, was that resolved? After that is repaired, clear the code(s) wait to see if the MIL stays off.
Do you have a code reader/scan tool?
Separately, I would suggest bringing the car to a recommended repair shop if further work is needed.
They just didn't put a new O2 sensor on because they said it was so rusted that it would probably break/strip if they removed it and then I would need to buy a new cat, etc...
No, I don't have a scan tool... :(
2002 SSEi
- nos4blood70
- Certified Bonneville Nut

- Posts: 9522
- Joined: Mon May 10, 2010 6:11 pm
- Year and Trim: 2003 SLE
- Location: Chicago, IL
Re: HELP! Service engine soon light blink, runs rough, bad s
If the misfire is fixed, the downstream O2 sensor is far less of an issue and won't affect the car much, if at all. Deal with this after the holidays, and like it was said above, go to an exhaust shop.


