You have 5 out of 8 cylinders misfiring. One bad wire is unlikely, IMO.

Vacuum leak which can affect the whole shebang is a great thing to suspect. I would want to know exactly what the test is, and watch it or perform it, myself. I would study every vacuum hose. Take it off, put it back on.

Or, it's still not clear whether damaged cats can cause that many misfires. After damaging the cats due to driving with misfires, like I said at the start. That's my naive guess. But I've never had a cat issue, so can't say with any cleverness.

I'm sure glad I'm not in your shoes tho. Good luck.

 

What size bolts hold the coil packs on? I have a similar problem and just realized whoever did the wires and plugs before I bought the truck never bolted the coil packs on..at all.

 

About 1-inch long and takes the 8mm socket. there are several that size located throughout the engine bay, if you can pull one and match it up at the hardware store. make sure the threads check out though

 

Thanks chubbs, I'll find one to match

 

if its not your lucky day then they can be a pain to get threaded. you have to scootch, pry, wedge, and so on to get the bottom 2 holes on the coil pack bracket lined up with the holes tapped in the block. a small socket and 8-10 inches of extension. take a tiny piece of plastic, enough to surround the head of the bolt and then stick it in the socket. that plastic usually is enough to hold the bolt tight enough so that you can maneuver it.

 

After putting a can of BG 44k in the tank.. all is well. Truck is running flawlessly with no lights on at all, and i haven't felt it misfire once even at idle.

Is this a temporary fix? Should i be proactive about "dirty injectors" and just replace them now, or is this a common problem?

 

Could have been a case of bad gas. I think you mentioned you only used Premium. I usually make it a point to only get gas from certain places that sell quality fuel and more importantly, high volume of customers. I was told once that if the fuel sits in the ground tank for a long time, it can lose it's quality, get contaminated, condensation, etc. Especially with higher fuel prices, fewer people buying premium - you want fresh fuel from a fresh tank at the station.

 

Don't throw money at injectors. Just drive the truck for a while. There will be lots of things you can spend money on later.

 

Truck randomly misfired on Cylinder 4 (P0304) while driving at 5 MPH after the block was warm...

Also noticing the "lifter tick" noise is pretty loud now, its embarrassing to drive through town.. Definitely a metal ticking noise like a lifter rather than a knock sound.

It does NOT happen while in park and revving, only while moving and happens immediately when i press the accelerator, and increases in rate with the engine.

Also noticed that my coolant has maybe gone down slightly after 200 miles?

Other than that, still running fine in terms of power, and drove it for 20 more miles today at freeway speeds and no issues or lights.