Ok. I put all new upper and lower intake gaskets on my 2001 Mazda tribute. It was having problems idling when it was cold. I put it all back together and it was running terrible and giving me a cylinder 3 misfire. Low and behold I forgot to plug in the wire for the injector. Plugged that back and it helped but it is now running rough mid RPMs say around 2000-3000 and giving back a code Saying "Bank 1 system too lean". I have cleaned my throttle body my MAF. I am gettin frustrated I can't figure this thing out. I need ideas. It seems like there is an intake or vaccuum leak because I can hear some hissing but I can't find it. Help me please!

 

Also I put a new fuel filter on it as well. I hope someone can come up with a solution soon this thing is pissing me off!

 

Any help here?

 

If you want to look for a vacuum leak, do the following:

• Completely seal the exhaust pipe(s) with duct tape
• Once again using duct tape, seal the end of a hose from an air compressor into the intake system somewhere up stream of the throttle body
• Turn on the compressed air supply
• Using a squirt bottle fill of soapy water, start spraying the entire intake system

If you have a vacuum leak, all you need to do now is look for the bubbles.

 

Does it sound like a problem a vacuum leak would cause?

 

Hard to tell; this is one of those things that is virtually impossible to diagnose with any certainty over the internet. Could it be a vacuum leak? Yes. Is it certain to be a vacuum leak? No way to tell (unless you test it).

 

Also I should add as one of the symptoms. It has a power loss and when you're going down the road you can feel the power change. Like it won't have as much power then all of a sudden you can feel it run like it should and have a power increase. It's weird. Havent tried testing for vacuum leaks yet.

 

Did this same repair a while back, sounds like a cracked / broken or loose vacuum hose. I'd go back over all of the hoses and make sure they are connected and in good condition.