WalRob1

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About WalRob1

  • Rank
    Observer (3-9 posts)

Previous Fields

  • Car Model and Year
    1996 Cadillac STS
  • Engine
    NORTHSTAR 4.6L V8 VVT (LH2)
  1. Jim, Is it reasonably easy to get to the O2 sensor in question and to replace it? Are there any diagrams or instructions you are aware of that I can review before commencing doing this? I have not been able to check the wiring you suggested. Is the EBTCM under the air filter? BTW, I checked the fuses, "50 Amp BRAKE MaxiFuse and the 10 Amp ABS fuse", which both do not look burned out. What was the third fuse? Thanks again wal
  2. Thank you very much for your kind assistance Cadillac Jim. My apologies for my tardiness - I have been traveling and did not have my login info. State of play: I ended up, with great trepidation, awfully carefully replacing the EGR myself. Since then, the engine has run smoothly (very occasional knocking), the MPG appears to be up by about 5MPG. There are no engine hesitation or stalling problems. Total cost about $50 instead of the $400 quoted! I just had it reinspected and it has failed on license plate lights only. So I'm roadworthy, once I've figured out how to access and change the bulbs. However, I'd love to sort out any remaining significant issues. Jim, the current full list of codes from the dashboard display. Note: With the ignition on but the engine not running (suffix H=history, C=Current): PC1139C PC1381C PC1571C RS0038C PZ2042C PC0174H PC0300H PC0603H PC1380H PC1602H PC1644H IP1552H NO ACM CODES NO SDM CODES NO TCS DATA PZ1558H IR1470H NO RFA CODES NO CCP CODES Does this modify your recommendations on how to proceed? Thanks again Wal
  3. Sometimes, when my foot is off the throttle and the engine revs get low (say under 1,000), the engine cuts out. The first time this happened it happened frequently over a couple of days then the problem disappeared for a month or so. Now it has returned and is more frequent. This occurs primarily as I come to a turning. Hence I'm using the brakes, foot off the throttle. If I can keep my foot on the throttle, I can sometimes avoid the engine cutting. But this is dodgy driving behaviour. The fault is however, intermmittent. It has occured once or twice when I've been cruising towards an exit ramp about to leave the motorway. Most of the time, it's at very low speed, on local roads, just before turning. If I sit in my driveway with the engine idling, the revs may fluctuate and the engine may cut out - but not always. Engineers I've spoken to have suggested the Throttle Position Sensor (TPS) is failing or that the Exhaust Gas Recirculation (EGR) valve may be sticking/broken. But nobody seems certain. The approach seems to be, "Could be X, let's replace that and see.", piece by piece. So far,I've spent over $800 trying to get this fixed, including needing to get the computer (ECM) replaced when an engineer tried to update it. With the replacement of the EGR quoted at over $400, I would really like a better sense of what is wrong. About 80 miles after replacing the computer, current dashboard displayed trouble codes are: PC1571, RS0038, PZ2042. Historic codes are myriad. Any help or advice you guys can give me will be gratefully received.