1998 Dodge Neon fuel sys 1 ol-fault/Multi missfire at highw

  • 1998 DODGE NEON
Electrical problem
1998 Dodge Neon 4 cyl Two Wheel Drive Manual

I keep getting a multi missfire (Generic) and OL-Fault Fuel sys-1 after driving on the highway for about 5-10 minutes. Ive also had the temp guage go crazy and spike all the way up and then go right back down. I might try to check the connection at the temp sender and/or replace it I was told that if the temp is not being read correctly it might give the engine the wrong info for fuel curves and that when the PCM gets a multi missfire code it puts the car in a limp in mode which might set the temp at a specific number even if its really reading wrong. Ive run the OBD scanner while driving and the temp stays at 199 Deg when the OL-Fault occurs and it reads multi missfire. Any ideas on where to start would be appriciated. The engine in a rebuilt with a Pacesetter header, MSD coil, flowmaster exhaust, and the Mopar EGR block Plate, (the EGR is still connected and to the best of my knowledge it does not send any data to the OBD). It has a new fuel pump and new plug wires and Ive tried 3 diff type plugs. Also while at highway speed and when the code is given the engine still runs great no hestitation or rough acceleration. Im also getting a bit of carbon at the exhaust tip like its running rich. Could this be a bad up stream or down O2 sensor? Or is it the EGR being blocked. Also im thinking of getting the Mopar PCM only because it a little cheaper than the AFX and its a bit more mild on the changes. I do know that it disregards the EGR and downstream o2 reading. Dont know if that would help with the ol fault/ missfire or not. Im just hoping that someone has had the same issue and can guide me in the right direction. Thanks for any help.
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have the same problem?
Friday, July 31st, 2009 AT 9:39 AM

1 Reply

Im going to add my OBD scan info so far Ive seen just,

P0300 Multi Missfire
OL- Fault Fuel Sys 1

The freeze frame at the DTC is:
Fuel Sys 1 CL
Load 21.18%
Engtemp 143.60 Def (F) (Low or Wrong temp?)
STFT B1 -3.13% (Trying to compensate?)
LTFT B1 12.50%
MAP 12.70 InHg
RPM 3072
Speed 67.11 MPH
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Tuesday, August 4th, 2009 AT 1:19 PM

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