Replaced valve cover gasket-bad idling afterwards

I removed the battery lead before starting with this process and now it does not want to idle (+-400rpm) and dies after a few seconds . I know about the VVTI relearning process but in those cases it just runs rough for 10-15 starts. Now it does not idle correctly after 15-20 starts.I have to keep it running by adding some rpms manually. It runs fine besides the poor idle nor does it skip a beat. Did I reconnect something in a wrong way?

 

Sounds like you either missed a vacuum line or the throttle body is dirty.

 

I would also say missed vacuum line because of the work you performed.

 

That and check to make sure the PCV valve didn't get stuck...

 

took of my intake manifold and throttle body recently. usally the first start is hard for my truck. starts and then shuts off right away. but then i restart it, and it idles around 1400rpm for a while.

im also guessing you left something not hooked up. look on the drivers side of the intake manifold. there are some big vacuum line that go there.

 

check all the connections you unplugged. Ima bet a coil pack or two or maf sensor is unplugged.

 

I wonder if OP forgot to connect the small vacuum hose behind the manifold plenum.

 

Thank you all. I checked both vacuum hoses and one had a small tear in it so replaced both.
Unfortunately to no avail.

Checked the PCV hose at the valve cover but this connected correctly.

Can it get stuck by my actions? I just disconnected the hose during the valve cover removal.

I checked all electrical connectors besides the coil packs and they are snug. If it is running smooth on all rpms besides idle, coil packs could not be unplugged right? It would be noticeable,right?

Yes it does not do that 1400 rpm start up routine. 800+- and then after 30 secs starts it rough 400 rpm idle.

 

Did you clean the throttle body?

 

No, should I? It was running fine before the valve cover gasket change.

 

I would, a battery disconnect resets learned values and if the throttle body is dirty the PCM doesn't remember the throttle position it has to be at to idle with a dirty throttle body after a battery disconnect so idle quality can be poor until it relearns or the throttle body is cleaned.

That may not be your problem but it's basically free to do and is a good first step in diagnosing a poor idle complaint after a battery disconnect.

 

It’s nice to clean once every 30-60k mile. But it won’t fix your issue.

 

I actually made a pic of the butterfly valve as I thought it was pretty dirty. I will see if I find the time to clean it.

 

Yes that is dirty...

 

reset your learned throttle values. i think you can do it by pulling the EFI fuse for 20 min. or you can use a bidirectional scan tool or techstream.

 

Thanks guys. I cleaned it and the problem is fixed. It ran rough after the first start as it needed to get rid of the junk which came off the butterfly valve
and dripped in the manifold. But 2nd start it ran like it supposed to do. Happy days.