Contour Enthusiasts Group Archives Forums General Troubleshooting Could this be a fuel pump?

Thanks for the replies re plugs and wires, I'm pretty sure there not the culprit - but it's worth checking again (~24 dollars for plugs vs 180 for a new pump! Wires were FMS 9mm). "Brand new" meant they were put in about 2 - 3 weeks ago, and have been running fine untill now.

Also, it seems very unlikely a misfiring plug could force an entire bank of cylinders to lean out at WOT - I'd think you'd end up slightly rich from the unspent fuel and get some backfires from it hitting the cats.

The chart of O2 is just plain ugly! Not only couldn't it hit the rich WOT state of about .89 - .90 volts, there are spots where it was truly lean (lean of stoich) at about .4 - .45, and only averaged about .5V This was continuous over the 5-6 seconds it took to trip the misfire code. After going back to normal cruising the engine smoothed right out and the O2 reads started to oscillate normally.