I would suspect something is getting hot, and failing, but, being able to just restart the truck, and the problem is gone doesn't really jibe with that. Try driving with the front O2 sensor unplugged, and see if anything changes.

 

Thank you for the replies!

yea it’s a strange smell almost like all the oxygen was pulled from the air just dry.

I had a muffler shop put a hole on both ends of the exhaust and check for flow issues. No clogs that their pressure test could find. I think the guy mentioned that the cat could be gutted or empty. It sounded hollow.

I replaced the front o2 sensor probably less that 5K miles ago with a NKG unit. The voltages on the sensors look decent. I will pull it to test anyway though. I will also rent a gauge to test the fuel pressure. It’s a newish fuel pump I replaced last year.

 

Here's something I ran into years back. Try pulling off the gas cap. If the tank ventilation system isn't operating properly, things like the gas tank purge system will draw a vacuum on the air above the gas in the tank, causing a loss in fuel pressure. Simple test and seconds to perform.

 

So noob questions, I pulled the fuel cap off and did not feel any vacuum while the truck was running. Was I supposed to test that while the truck is having the issue?

With the o2 unplugged the system will code but the PCM will default to a fuel trim level it determines correct? Or was I just supposed to unplug it from the cat and put it up somewhere?

I am going to rent a fuel pressure gauge tomorrow to double check that end.

Something else I discovered unfortunately. I decided to check again for a plenum gasket leak (despite having replaced it close to a year ago with a new aluminum plate) - Pulled the throttle body off and looked in - Sure enough there is a 1 inch strip of oil at the very back of the plenum. I suppose that's enough to cause some issues... I wonder if that is my high RPM issue because I have checked the TV and dumped the pan again and I didn't see anything. That would not cause an issue with no throttle though would it?

 

Unplug the electrical connector. The PCM will then just run off pre-programmed tables for fuel trim, which tend to be a bit rich. If it runs better with the O2 unplugged, replace the sensor. (NTK or Denso only please.)

 

Run around without the gas cap so if the purge system is malfunctioning, a vacuum in the gas tank can't be built up.

 

Hey yall, just wanted to give a quick status update. Figured I would try to get one more opinion before I send her into a shop.

So I spent the past few days looking everything over with a friend, ran through 2 cans of break cleaner testing for air leaks and found nothing. Rented a fuel pressure system and tested the fuel pump which tested fine. Pulled the o2 sensor and drove to work same issue, tried the gas cap as well.

Since my last post the truck developed a new issue and the old issue sort of.. went away? It hasn't happened again. I have had this issue before but seems to be a little different this time:

Probably about a day after my last post I was sitting at a stop light, felt like the truck coughed for a second and I would tell something was wrong. The truck will idle correctly around the 600RPM mark but the idle is a little more pronounced. Almost shaking like I am getting a mis. Still no codes. As I begin to drive the moment I hit 41MPH the truck shakes violently, like the engine is about to leave the engine compartment, it does this all the way to 60MPH. If I get the throttle to about 40% and the RPM's to about 2K the shaking stops, but If I lightly press the gas peddle it shakes so bad to the point my dash started to come apart. I know its a misfire but still no codes. If I am at a light and I am stopped I can hear a faint ping like metal hitting metal coming from what sounds like the exhaust. When this happened before I actually had gotten misfire codes.

So I dropped the oil checked for metal, checked all the spark plugs and wires. Threw some fuel cleaner in with all new gas. Ordered parts for a full tune (has not even been 3K miles since I last replaced the spark plugs and wires) New cap and rotor so I am waiting on all of that. I did a boat load of research into my issue and people mentioned rocker arms and broken valve springs, so I pulled off both valve covers and inspected everything, ran the engine and everything ran perfectly nothing appeared to be stuck or broken.

I do not really know why I did this but I remembered reading a post about someone mentioning they disabled OD because their issue appeared to be RPM related. I looked down at my dash (going 60MPH because the shaking isn't as bad) and I noticed the needle bouncing lightly between 1.5 and 1.6K like its struggling. So I decided to push the OD button on my shift lever, the OD/OFF light came on and the RPMs shot up to about 2.3K and immediately the shaking went away. I slowed down to the next red light but the truck's idle was still off, can still sort of hear a misfire. Started to drive and at about 35-40MPH there is a slight shake but nothing like it was, from there everything is incredibly smooth. I drove it the same way to work today, but as I was avoiding a red light I hit the gas got to about 4K RPM and the check engine light came on and blinked for 4 seconds, I finally got a code for a cylinder 7 misfire.

I am going to try a full tune up again but if this does not fix the problem I suppose I will send her into a shop. Just wanted to get your thoughts before I did that.

 

You have a misfire, multiple cylinders from the description..... at right about 41mph, the trans will lock tcc, and drop into overdrive, giving you a direct mechanical connection from the engine, to the tires. If you have a misfire, THAT is when it is going to be most pronounced. And yeah, just two cylinders misfiring there will feel like the truck is trying to shake itself apart.

First think I would check is your firing order. The way the cap is situated in these trucks, it is REAL easy to swap a couple wires into the wrong spots, and it gives you exactly the symptoms you describe. Also, what plugs do you have in there? These trucks really dislike the rare-earth plugs.... and mystery misfires are a direct symptom of those.

 

The last time this happened to me you mentioned to only run the copper plugs, since then I only put in the copper NGK V-core plugs. I will double check the fire order to see if I messed something up. I ordered all new plenum gaskets and I will make that repair again. Just really odd that this happened and my other issue of no throttle response stopped happening. Confusing the hell out of me. Thanks HeyYou, parts come in this weekend I will let you know what I find.

 

You didn't read the fine print in the contract when you bought the truck, did you? "Keeping your life interesting." is only one of the bullet points in there.