surgeing with gas cap off

[Adam Marcum]

ok this is happened the last three times i have put gas in the car. when i remove the gas cap while the car is running it starts to surge bad from 400 rpm to 1200 rpm. almost like the old mustangs would do when they had a bad map sensor. car 99gs.

[Bonneville92V688]

Hmm... I guess I will be the first to ask....

Why are you putting gas in the car with it running?

Any SES on the dash or stored codes?

[00Beast]

The car pulls a vacuum through the Evap system, so theoretically it could cause a vacuum leak.

Isn't it illegal to put gas in a car while running? Why is it so important to people to leave their car running while fueling? It's 2 minutes, not like the car is going to go stone cold... The only vehicle I would ever put fuel in while it's running is our Duramax pickup, as diesel doesn't ignite from spark, and it's more fuel efficient for them to run for 5 minutes than to shut them off and re-start during that time.

[Adam Marcum]

well it is getting cold and usually the wife and kid are in the car. and it is doing it a little while running.and no codes

[00Beast]

Um, now you're not only putting your life at risk, but your family's. Not smart.

When were plugs and wires done? Have you checked for vacuum leaks?

[Adam Marcum]

plugs and wires done about 3 months ago. no vacuum leaks that i have found..and don't forget not just me and the family but everyone else too.

[viper8907]

Unless it surges with the gas cap on as well, I don't see a problem. The surging is because the gas cap is off, and like Ed said, it creates a vacuum leak. It isn't made to run with the gas cap off.

[BlackHawk99]

There's definitely an issue somewhere, not that I know what it is. We had an 01 GS and I filled it up several times while it was running and never had this issue (same as I do with all of the cars we've owned).

[Adam Marcum]

i no it never did it before .it just started this so i will try to find the problem myself. i got a lot of help from this place that's why i still visit here.and not club gp and other sites that people flame you for other stuff when you ask about a problem.this is a good place for help.

[Adam Marcum]

ok update. code p0304=misfire #4 and p1441=evap system flow during non purge?..and here is a scan.hope i did this right if not feel free to edit please. and tell me how to post a scan.
Frame 0 Time 0.0


MIL STATUS OFF
ABSLT TPS % 0.0
ENG SPEED RPM 700
CALC LOAD % 1.5
MAF FLOW GR/SE 4.31
MAP KPA 36
COOLANT F 194
IAT F 73
IGN ADVANCE DE 27.0
ST FTRM1 % 1.5
LT FTRM1 % 13.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.870
ST FTRM11 % 0.7
O2S12 V 0.760
OBD2 STAT CA

Frame 1 Time 0.8


MIL STATUS OFF
ABSLT TPS % 15.2
ENG SPEED RPM 2033
CALC LOAD % 15.2
MAF FLOW GR/SE 43.89
MAP KPA 84
COOLANT F 194
IAT F 75
IGN ADVANCE DE 28.5
ST FTRM1 % 4.6
LT FTRM1 % 2.3
VEH SPEED MPH 17
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.145
ST FTRM11 % 1.5
O2S12 V 0.230
OBD2 STAT CA

Frame 2 Time 1.4


MIL STATUS OFF
ABSLT TPS % 100.0
ENG SPEED RPM 4460
CALC LOAD % 75.2
MAF FLOW GR/SE195.17
MAP KPA 154
COOLANT F 192
IAT F 73
IGN ADVANCE DE 12.0
ST FTRM1 % 0.0
LT FTRM1 % 4.6
VEH SPEED MPH 42
FUEL SYS 1 OPEN1
FUEL SYS 2 N/A
O2S11 V 0.965
ST FTRM11 % 0.0
O2S12 V 0.910
OBD2 STAT CA

Frame 3 Time 2.1


MIL STATUS OFF
ABSLT TPS % 100.0
ENG SPEED RPM 3963
CALC LOAD % 65.4
MAF FLOW GR/SE173.73
MAP KPA 156
COOLANT F 190
IAT F 64
IGN ADVANCE DE 12.5
ST FTRM1 % 0.0
LT FTRM1 % 4.6
VEH SPEED MPH 61
FUEL SYS 1 OPEN1
FUEL SYS 2 N/A
O2S11 V 0.950
ST FTRM11 % 0.0
O2S12 V 0.915
OBD2 STAT CA

Frame 4 Time 2.7


MIL STATUS OFF
ABSLT TPS % 0.0
ENG SPEED RPM 3118
CALC LOAD % 4.3
MAF FLOW GR/SE 10.45
MAP KPA 21
COOLANT F 190
IAT F 60
IGN ADVANCE DE 28.0
ST FTRM1 % -8.0
LT FTRM1 % 14.8
VEH SPEED MPH 65
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.130
ST FTRM11 % 0.0
O2S12 V 0.795
OBD2 STAT CA

Frame 5 Time 3.4Recorded Data

MIL STATUS OFF
ABSLT TPS % 0.0
ENG SPEED RPM 683
CALC LOAD % 1.5
MAF FLOW GR/SE 4.38
MAP KPA 36
COOLANT F 192
IAT F 69
IGN ADVANCE DE 27.0
ST FTRM1 % -4.6
LT FTRM1 % 13.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.075
ST FTRM11 % -4.6
O2S12 V 0.720
OBD2 STAT CA

Frame -5 Time -3.2


MIL STATUS OFF
ABSLT TPS % 0.0
ENG SPEED RPM 702
CALC LOAD % 1.5
MAF FLOW GR/SE 4.37
MAP KPA 35
COOLANT F 194
IAT F 69
IGN ADVANCE DE 27.0
ST FTRM1 % -1.0
LT FTRM1 % 13.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.150
ST FTRM11 % -1.0
O2S12 V 0.660
OBD2 STAT CA

Frame -4 Time -2.5


MIL STATUS OFF
ABSLT TPS % 0.0
ENG SPEED RPM 697
CALC LOAD % 1.5
MAF FLOW GR/SE 4.37
MAP KPA 36
COOLANT F 194
IAT F 71
IGN ADVANCE DE 27.0
ST FTRM1 % 0.0
LT FTRM1 % 13.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.320
ST FTRM11 % 1.5
O2S12 V 0.110
OBD2 STAT CA

Frame -3 Time -1.9


MIL STATUS OFF
ABSLT TPS % 0.0
ENG SPEED RPM 694
CALC LOAD % 1.5
MAF FLOW GR/SE 4.34
MAP KPA 35
COOLANT F 194
IAT F 71
IGN ADVANCE DE 27.0
ST FTRM1 % 0.0
LT FTRM1 % 13.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.150
ST FTRM11 % 1.5
O2S12 V 0.095
OBD2 STAT CA

Frame -2 Time -1.3


MIL STATUS OFF
ABSLT TPS % 0.0
ENG SPEED RPM 688
CALC LOAD % 1.5
MAF FLOW GR/SE 4.32
MAP KPA 36
COOLANT F 194
IAT F 71
IGN ADVANCE DE 27.0
ST FTRM1 % 0.0
LT FTRM1 % 13.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.115
ST FTRM11 % 1.5
O2S12 V 0.070
OBD2 STAT CA

Frame -1 Time -0.6


MIL STATUS OFF
ABSLT TPS % 0.0
ENG SPEED RPM 690
CALC LOAD % 1.5
MAF FLOW GR/SE 4.32
MAP KPA 36
COOLANT F 194
IAT F 73
IGN ADVANCE DE 27.0
ST FTRM1 % 1.5
LT FTRM1 % 13.2
VEH SPEED MPH 0
FUEL SYS 1 CLSD
FUEL SYS 2 N/A
O2S11 V 0.360
ST FTRM11 % 3.9
O2S12 V 0.085
OBD2 STAT CA