P0171 penidng trouble code, replaced valve gaskets..

This past weekend, I removed the valve covers and intake maifolds, to replace the valve cover plugs at the rear of the engine where there was a small oil leak. I also replaced the two intake manifold gaskets, and throttle body gasket, since I've broken the seal on them a couple times before.

Put everything back together and drove off, and with in a few miles the engine threw the infamous P0171 (MAF) check engine light. I cleared the code just incase it was something I did while I had the MAF sensor disconnected during the valvle cover work. And with in 2 miles, the CEL was back again.

I removed the MAF, cleaned, and reinstalled it. The code did not clear it's self right away, so I cleared it again. Now I've driven about 15 miles and no CEL, but the Ultragage keeps giving me a "Pending Trouble code of P0171".

It's possible that I didn't fix the MAF sensor at all, is this pending just something that will go away?I'm at 178k miles and have not had an issue with the MAF.

I just think it's weird that the MAF went bad all of a sudden after removing MAF, elbow, TB, manifold.

I've look everywhere for a loose vacuum hose, and everything seems to be in it's place.How likely is it that an air leak in the intake manifold is causing this? I torqued all the bolts to the specified 13 ft. lbs.

Is it possible the MAF just needed to be cleaned and it's a coincidence that it happend as soon as I replaced the gaskets?

Is a pending no big deal? I guess i wouldn't even notice it if the Ultragauge wasn't connected since the pending doesnt throw the CEL?

Any help woud be greatly apprecited

 

I did disconnect the injectors to remove the valve covers, but I know I reconnected them, unless one loose. But your right, that would throw some other code, or the truck would be running rough. Right now, the truck is running perfectly smooth.

 

CEL came back on....this sucks...it could be anything.

 

Dumb question ....which is that one?

 

You guys are also forgetting one major thing here with a lean code. Lean codes can be caused from an intake manifold gasket leak. Since you just worked on the truck, and this code was not present before, I suspect that you have an improperly installed or leaking intake manifold gasket. To test this, get a can of spray carb cleaner and spray around the area of the intake manifold where it meets the cylinder head. Look at you Ultragauge at your fuel trim data. If your fuel system goes suddenly rich, there is your leak.

 

I did install two brand new gaskets on the manifold and a new gasket on the TB.

I was planning on taking everything back apart this past weekend, but I was shipped off to Tampa for the RNC for a couple weeks. So the truck is sitting in the garage for a while.

I was wondering if the take had a leak since I used new gasket. I really thought that a13 ft. Lbs of torque was usually low.

Thank you for the suggestion. I'll have to try this when I get back.

 

Spec for the intake manifold is 21ftlbs. Even new manifold gaskets can accidentally get trash caught on the edges, etc, causing leaks, but your torque spec is also wrong.

 

I swear the FSM said 13. I thought it was weird. That might be the issue.

Is the TB also 21?

 

Back in town and preparing to disassemble this again.

Can anyone confirm if the throttle body is 21 ft. lbs as well?