My 4L SOHC set codes & failed state inspection

kponhlo · 06-10-2005, 10:30 AM

Please help. My '97 4L SOHC set Powertrain codes 442, 420 and 174. Not havng a lot of time or $$$ right now I tried clearing them to pass the new OBDII state inpection but then failed anyway - I have to drive it 200 miles so it can reset the codes and they gave me ten days to do that.

According to the book, the codes mean the following:

442 - EVAP small leak detected
420 - Catalytic system bank 1 efficiency too low
174 - System adaptive fuel too lean on bank 2

It idles a little rough when warm; during winter it would race, then bog, then race again during warmup. I have heard about the plastic intake/gasket issue, and have even bought the gaskets. Will that fix any or all of the described symptoms/codes???

I didn't have to drive it much for the past year or so, but now I really need it. Any thoughts are greatly appreciated.

Thanks,

-Keith

captTelescope · 06-11-2005, 01:32 AM

Here's a few suggestions on where to start.

For the 442, examine your hose connections to/from the EVAP cannister. Look for possible leaks. Fix anything suspicious. Make sure your gas cap is on tight and doesn't leak.

The 420 code is likely to hurt. It could be the Cat, but also O2 sensors. Suspect the downstream sensor (on the Cat's outlet). If you don't have proper diagnostic equipment, you could waste a lot of money throwing expensive parts at this problem. Or you could take it to a dealer (ouch) and get 'er done.

The 174 could be clogged fuel injectors, especially if the Ex has been sitting. Try a FI cleaner. That's cheap enough. Or it could be the upstream O2 sensor. Or the fuel filter. Or the fuel pump, check fuel pressure. Again, the dealer (theoreticly) could fix you right up.

*CDW6212R* · 06-11-2005, 12:04 PM

Do as much of the tune up work that you can, before having to go to a shop. Include the normal stuff, and fuel injector cleaner, possibly Seafoam too. Good luck,
Don

06-10-2005, 10:30 AM	#1
kponhlo Wannabe Elite Explorer Niskayuna, NY '97 XLT Join Date: Aug 2003 Posts: 26 Vehicle Specs (Original Poster)	My 4L SOHC set codes & failed state inspection Please help. My '97 4L SOHC set Powertrain codes 442, 420 and 174. Not havng a lot of time or $$$ right now I tried clearing them to pass the new OBDII state inpection but then failed anyway - I have to drive it 200 miles so it can reset the codes and they gave me ten days to do that. According to the book, the codes mean the following: 442 - EVAP small leak detected 420 - Catalytic system bank 1 efficiency too low 174 - System adaptive fuel too lean on bank 2 It idles a little rough when warm; during winter it would race, then bog, then race again during warmup. I have heard about the plastic intake/gasket issue, and have even bought the gaskets. Will that fix any or all of the described symptoms/codes??? I didn't have to drive it much for the past year or so, but now I really need it. Any thoughts are greatly appreciated. Thanks, -Keith

06-11-2005, 01:32 AM	#2
captTelescope Wannabe Elite Explorer Orange County, CA 98 XLT 4.0 SOHC 4WD Join Date: Aug 2003 Posts: 38 Vehicle Specs	Here's a few suggestions on where to start. For the 442, examine your hose connections to/from the EVAP cannister. Look for possible leaks. Fix anything suspicious. Make sure your gas cap is on tight and doesn't leak. The 420 code is likely to hurt. It could be the Cat, but also O2 sensors. Suspect the downstream sensor (on the Cat's outlet). If you don't have proper diagnostic equipment, you could waste a lot of money throwing expensive parts at this problem. Or you could take it to a dealer (ouch) and get 'er done. The 174 could be clogged fuel injectors, especially if the Ex has been sitting. Try a FI cleaner. That's cheap enough. Or it could be the upstream O2 sensor. Or the fuel filter. Or the fuel pump, check fuel pressure. Again, the dealer (theoreticly) could fix you right up. __________________ Red! 1998 Explorer XLT, 4WD, 4.0 SOHC Pinstriping by Desert Vegetation Free advice... worth every penny.

06-11-2005, 12:04 PM	#3
CDW6212R Elite Explorer Knoxville, TN 98 Mountaineer A4WD Join Date: Jun 2004 Posts: 12,949 Vehicle Specs	Do as much of the tune up work that you can, before having to go to a shop. Include the normal stuff, and fuel injector cleaner, possibly Seafoam too. Good luck, Don __________________ Don 91 Lincoln LSC/SE, 99/93 Explorer Limited 4WD, 98 AWD Mounty with 255/55/18's, big sway bars, and 12.75" x 1.25" rotors. Soon a BW4406, built trans, stereo and interior. The best thing that could help us all, is the Fair Tax Plan. Be American, Buy American (Manufacturer)