2002 Grabd Am 3400 SFI runs bad

[Sidecar]

The problem is that the motor will only do about 3500 RPM and stumbles under load. Doesn't stall though and idles just fine. I have put a Snap-on scanner on it. The scanner reported the speed sensor signal was low. I changed the speed sensor, no difference, checked the speed sensor line with the computer connected, ignition off, it appeared to be grounded. Checked the same line with the computer disconnected, it was no longer at ground potential. Checked the continuity of the line and it was fine all the back to the computer. The service vehicle soon light comes on as soon as you put the car in Drive and pull away from the curb. Does any body know what this light is for or what problems it reports. The check engine light does not come on to indicate a problem, These are two different lights on the dash. I have changed the TPS as well, no difference. I have changed the plugs and wires, no difference. I have changed the coil pack, no difference. Turn off the traction control and the motor runs worse. The car has only 167,000 km on it and is really good shape otherwise. Has anyone got any ideas where I should look next? Thanks in advance for the help.

[Superdave]

try replacing the MAP sensor and/or the MAF.


the MAF is going to be expencive, might be worth grabbing one from another car at the junk yard. Also try cleaning yours with some MAF cleaner avaliable at the parts store.

[sprucegagt]

The SVS light is in no way related to an engine problem, the SES light is for that. I'd check your headlights for the SVS problem. The DRL system uses the high beam filament and it will know when one of those filaments are bad.

Simple question, but after changing the speed sensor did you clear the code? Does your speedo work? The car may be in some sort of limp mode due to the code being set.

[Sidecar]

Yes I cleared the code after changing the speed sensor and the speedo does work. I'll check the headlights too. Thanks for the tip

[geldartb]

one of your high-beams is prob burnt out. the Daytime lights dont come on till you put it in drive so thats where the SVS light comes from.

have a friend stand in front of the car when you put it in drive