Help please? I didn't use my truck for about 2 weeks and now it sputters badly when I try to start it and dies immediately if I don't keep foot on pedal. If I get the rpm up to about 6000 it starts dropping in power and surging. It always dies as soon as I let up the gas. I bought an OBDC reader which initially didn't work (fuse in truck was blown which also surprised me) and after I swapped fuses, the codes it brings up are P0351, P0511 and P0353. I know the codes are for Ignition Coil A circuit, Idle Air Control Circuit, and Ignition Coil C Circuit but I am struggling as to what that means. I've never had any issues with this vehicle (bought new) until now. I have taken off the IAC valve and cleaned it out, also sprayed cleaner into the air control itself, no help at all. Additionally, not sure if this is related or when it happened, but there is a sensor on the top of the engine on the left side, and the wire is completely disconnected, like 2 inches just cut away and gone. I have never noticed that before (picture below). What is that sensor and is it related? Thank you all for any help or pointing me in the right direction! I try to do things myself when I can, but I need some pointers to get me there.

Sensor with cut/missing wire

 

Welcome to the forum

P0351 Ignition Coil A Primary/Secondary Circuit Malfunction
P0353 Ignition Coil C Primary/Secondary Circuit Malfunction

These codes means the Computer(PCM) is not getting feedback that the A and C coils are firing

The coil pack has 3 coils inside, A, B, and C, each coil sparks 2 cylinders at the same time, 1/5, 2/6 and 3/4
So engine is only running on 2 of its 6 cylinders most of the time

First unplug the 4 wire connector on coil pack, have a look inside it for corrosion, plug it back in, this unplugging and plugging back in cleans the contacts on any connector
Now unplug each spark plug wire on the coil pack and plug it back in
Clear codes
Restart engine

It reads like you also have a large vacuum leak, 4.0l SOHC was known for leaking PCV Valve hose at the elbows

Longshot
If vehicle was sitting for awhile is it possible someone siphoned off some gasoline and replaced it with water, that will cause similar symptoms and codes


As for the broken wires, it may be for the Knock Sensor but there should be a code for that, wouldn't cause your current issue
See if you can get the wire colors, that's the easiest way to ID what they are for

 

Thank you for that info. I tried your suggestions on the coil pack no luck. Also found a broken vacuum line going into a valve on top of the inlet manifold. Still trying to figure out what is what in here. I think the line is part of the fuel injector vacuum lines. I patched it for now but still having same issue. May need to siphon fuel out and try fresh. Will keep at it...

 

Try 50/50 test
Spray fuel into the engine manually while try to start it and see if it runs smoother
Pull off the large air tube and leave it off the intake end, make sure fan won't hit it, then spray in fuel while engine idles to see if injector/fuel issue is causing the rough running and misfires

No vacuum used in fuel injection system

 

Ok will try that... Here is pic of that broken vacuum line:

 

That's for the EGR valve, you can see the other end of it in the picture
Easy to repair with a short piece of regular vacuum hose

The stuff over the green vacuum line is called split wire loom, protects the line, cut off a bit of the loom on both ends of the broken line, install tight fitting vacuum hose on both ends to splice them together, no clamps are needed.................its a VACUUM line, so sucks in and holds the splice together, so not like a "pressure" connection that tries to push apart a splice

 

Well it turned out to be multiple electrical wires chewed by rodents... Most likely squirrels. Frustrating but finally fixed and back to normal.

 

Good work
Thanks for the update, it was an odd one