I've noticed something that gave me that impression. My 97 XJ trips a SES light or MIL light below 1/4 tank every two or three tank fulls. Never misses a beat, light goes out when it is filled up, usually when pulling out of th egast station lot! I need to get the code, but it obviously is not domething very serious. Any ideas? My first thought was to replace the fuel cap as it is 10 yeasr old now. -- Mark Price Morgantown, WV 1969 AMC Rambler, 4.0L, EFI, T-5 -------------- Original message ---------------------- From: Kelly Hardie <keleigh3000@xxxxxxxxx> > As someone who deals with OBDII systems on a daily basis, I'll tell you > that monitoring engine efficiency and performance is somewhat of a > secondary function for the oxygen sensors. Their primary functions are > 1) maintaining catalyst efficiency and B) monitoring other control > systems for errors. These systems are so sophisticated and so dialed in > that you'd never notice the difference under 99% of conditions if you > disconnected them (assuming everything else is working correctly). > Customers with bad lambda sensors almost never have driveablity > complaints, only "MIL on"... > > Kelly > > Sandwich Maker wrote: > > " From: Tom Jennings <tomj@xxxxxxx> > > " > > " The only thing I've read "bad" about Howell and others is from > > " people who tried to set them up without enough sensor feedback, > > " "open loop", and feedback is the whole POINT of FI. Except for > > " those few, I've not heard a bad thing about Howell. > > > > i disagree about feedback. it's the only practical way to zero in on > > perfect mixture under widely and wildly changing conditions, but i've > > always thought that to a degree it was a crutch for systems that > > didn't have the proper sensors to read the environment going in. our > > injected '71 saab didn't have no stinkin feedback and it had more hp, > > ran better, and got better mileage than our otherwise-identical carbed > > '71. as far as i could determine, the engines were identical > > internally; only the induction system differed. this was btw an > > analog system, based afaik on bendix patents that may have been on the > > '57 rebel system. > > ________________________________________________________________________ > > Andrew Hay the genius nature > > internet rambler is to see what all have seen > > adh@xxxxxxxxxxxxxxxxx and think what none thought > > _______________________________________________ > > Amc-list mailing list > > Amc-list@xxxxxxxxxxxx > > http://www.amc-list.com/mailman/listinfo/amc-list > > > > > _______________________________________________ > Amc-list mailing list > Amc-list@xxxxxxxxxxxx > http://www.amc-list.com/mailman/listinfo/amc-list _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list