I hope someone can help with this. 1998 Contour GL 2.0 liter engine (CNG) Car has been running just fine. And just like night and day it starts to idle very rough. Now, when you give it gas it seems ok but a little under powered. At a stop light, etc it starts huffing and puffing like an asthmatic and wants to stall. Several times as I have rounded a corner it has completely stalled. The only codes I get are the P 0171 (lean bank 1). I have replaced the following...PCV and tubing, MAF sensor and body, O2 sensor, plugs, fuel filter, oil dipstick, and timing belt. Not one of these changes (which Ford suggests) have resulted in any improvement. What possibly have I missed?
jaycoward@copper.net

 

I could have saved you the time on the timing belt. Lean bank 1 means the "1" side of your engine or possibly number one piston isn't getting enough fuel. Look for a blocked/kinked line, check fuel pressure, clean and repair or replace injectors on bank "1" (after you relieve fuel pressure and remove the necessary parts).

 

I checked for kinked lines and found nothing unusual. However this bit of info may help to solve the problem. After removing the section of intake hosing between the throttle cover and the MAF sensor body, I started up the vehicle and it seemed to idle nice and quitely for quite some time. So I proceeded to place this piece of hosing back on and as soon as I put it into place, the engine died. I left one end connected at the throttle body cover and left the other end exposed, started her up again and she ran smooth. Placed the hosing onto the MAF unit and the car died again. After that I tried the same thing again, but could not get the car to idle smoothly. Any suggestions?

 

Not sure which hose exactly - but is there any blockage in the hose? If not one of the ends where it plugs in is experiencing a problem. Either one end has blockage or computer senses something differently with it connected that it doesn't like. If it runs better with it off I'd keep it off until I was sure what's going on with it. Does your engine have high mileage?

 

No blockages between the air filter and the throttle body. The hose I was talking about is the tube between the MAF and the throttle body cover (about 2' in diameter). Here is a bit more info...Started it up this morning, could barely keep it going, but finally got on the way. Drove it for about 1/2 hour. During this time I had several stop lights and could barely keep it going by shifting into neutral and giving it some gas. It smelled awful. Almost as if the cabin was filling up with semi burned fuel. I also noticed that there was still smoke coming out of the tailpipe. It appeared to be white but it did stink. Once you get moving you do not notice the smell, only when you are at a stop and it stinks. The trouble codes currently are as follows P0171 and now P0102. The 102 is brand new. The MAF is new as well. The air filter is new as well. It is also going through gas like a sieve (probably has something to do with the stink). Any help?

 

If it smells like a sulphur/rotten egg it's probably a shot catalytic convertor.

 

Does not smell like sulfur, more like partially burned fuel. Kind of chemical smell, but not sulfurous at all.

 

This may sound odd - but are you losing antifreeze? Speed sensor could be weird, and account for over or under fueling but what's weird is the computer says it needs fuel at bank 1 and you smell fuel not quite burnt like it's coming out before it makes it there. Have you had any leaks while it's running?

 

I'd almost say a leaky seal at the injector, but you could see that drip/leak I assume.

 

I don't see leaky fuel or antifreeze, oil or any fluids. I find this extremely odd as well. I keep getting the 0171 code (now I am also getting a 0102) but I am going through gas much faster than I was.