My truck has 207,000 miles but I put a remanufactured long black in about 40,000 miles ago. It has never gotten over about 17mpg. Now it averages 13.5mpg driving to work(4.5 miles each way). Some days it runs very well, some are awful. The following syptoms come and go in any combination.

• Won't idle, have to pat the pedal at red lights.
• Has a slight miss.
• Has a bad miss that's like you have shut the key off. When it gets this bad it pretty much won't run unless you hold it wide open. Then it will usually backfire.

It's always down on power, but worse when it's having a bad day. These have gotten worse over the last couple of years and seem to be picking up steam in the last month or two. I just got the following codes out.

• 21** 02s sensor does not detect rich or lean condition (signal stays at center)
• 52** Fuel system rich
• 32** EGR Solenoid circuit short or open condition detected

I would appreciate any help you all can give me.

 

Looks like you need a new O2 sensor. The EGR code isn't a big deal unless the valve is stuck open, which is unlikely.

 

Thank you for the response. It was having one of it's bad days today so I had one of the mechanics where I work look at it. He shot the heads with a digital thermostat, and a couple of spots beside the plugs were very cool. He also found a couple of bad spots on the plug wires. So I put a new set of Bosch wires on it tonight and just drove it with little or no improvement. I've not put the O2 sensor on yet. He says that it couldn't make it run as badly as it does so there has to be other problems. Others have suggested a coil. I think it has good fuel pressure(about 42-45 psi at idle).

 

A bad o2 sensor WILL make it run like crap. I've been there. Especially one that's been bad for TWO YEARS!!!! Also believe it or not, a bad battery will too (without showing the usual "bad battery" signs). When I needed a new battery, my truck would die on me at stop signs, and wouldn't idle correctly. I'd have it tested just to be sure. And if it's been acting funny for 2 years...... well I guess better late than never to figure this thing out lol.