I've never had a problem with emissions on a 240/740 before, but my 1987 240 project car has failed. The problem is carbon monoxide... allowable is 1.2%, my car was 4.7%. (hydrocarbons were OK... allowable is 220 ppm, my car was 159 -- also carbon dioxide was 12.2%).

This car was sitting for 6 months before I got it, and it came with a full tank of 6-month-old gas. I drove it hard on the highway for about 15 miles before taking it into the inspection shop, hoping to clean out any gunk and crud that could potentially give me problems. Guess that wasn't good enough.

My next plan is to get rid of the 6-month-old gas, fill up with super unleaded and a can of gumout fuel system cleaner, drive till empty, fill up with regular unleaded, and then try the inspection again.

Any ideas? Will this problem clear itself up with more highway driving and fresh gas or do I need to start testing electrical parts and fuel pressure? BTW previously I was having a compression problem in 1 cylinder in this car but I think that was due to a weak battery (I measured previously, in order, 170, 170, 150, 90). This morning I measured 170 PSI in all 4 (cold and without squirting in any oil). Also when I had the intake manifold off a couple days ago, I was amazed at how clean everything was... no signs of a bad injector or anything like that.

Thanks for any and all help!