Welcome Visitor! Please take a few seconds and bdagle
New Member
- Joined
- Aug 12, 2007
- Messages
- 11
- Reaction score
- 0
- Points
- 0
- Age
- 79
I thought that you might find this interesting. Several weeks ago my 2001 Ranger 2.3 truck started idling very poorly. At idle it would run very rough and miss, it ran just fine off idle. It showed a trouble code P0171, which means that it was running too lean. However you could smell that at idle it was actually running rich. A scanner showed that the O2 sensor would go full lean and not switch at idle. All this points directly to a vacuum leak. So I checked every hose and every connection to the manifold, no leaks. I disconnected the EGR valve tube and plugged the hole, no difference. I changed the plugs and tried a new ignition coil pack, no change. I tried a new IAC valve and checked it’s gasket, nothing. I then took the exhaust and the cats off to make sure that air wasn’t getting in and messing with the O2 sensor reading, every thing was good. Cleaned and checked the mass airflow sensor, throttle body, and it’s air duct, still not the problem. A vacuum gauge showed the engine vacuum to be a little lower than it should have been, but not much and with the engine rolling so badly it was hard to tell because the vacuum was swinging up and down. Finally tonight with the engine fully warmed up and missing away at idle, I started spraying carb cleaner at the where the branches of the manifold meet the cylinder head , no difference. Now the carb cleaner comes out pretty fast and splashes all over the place, when I sprayed the IAC valve the idle soothed out for a second! I got a strong light and looked into the recess in the plastic manifold between the IAC valve and the throttle body. I could see a little hole in the plastic and if I put my finger over the hole the idle smoothed right out. I used a sheet metal screw and some epoxy to plug the hole and the truck runs and idles just perfect. Incredible! The only thing I can figure is that this must have been a weak spot when the manifold was cast?
BD
BD
