Ok, truck is in my sig. I am getting ready to go out and start digging into this, and am looking for some insight that you folks may have, so I don't miss anything stupid.

Truck starts and runs fine cold. As the temp gets to around 160 or so, it starts dropping cylinders. Mostly 1 and 6. (hard codes for those.) Also getting a coil control circuit code. (along with some trans codes for O/D, and TCC, but, don't believe those relate to this particular problem.) Once it starts to miss, those cylinders simply stop working, until the engine cools completely. Most evident when shifting into O/D.

O2 is a denso unit, less than two years old. Engine consumes oil like it is going out of style, even though the plenum is still squeaky clean. (replaced a year or two ago.)

Coil has been replaced about a year ago. (stock replacement.)

Fuel pressure is good, 48 PSI at idle.

I ran a compression test on the motor a while back, and 6 had zero pressure.... 2 and 4 were at 60 PSI. What really throws me though, is about a week after that test, the engine stopped missing, and ran fine, regardless of temp, for more than a month. This all started recently. (last couple days.)

Engine has 187K miles on it.... Yeah, its tired.

I am planning on checking the coil, pulling the valve cover, and looking for broken valve springs. (though I don't get any valve train noise.) Possibly swapping some injectors around. I am looking for additional input from the community here, to see if anyone else has any suggestions.

 

I would do a comp test on it again just for comparison reasons. Other than that bud you know the routine as good if not better than most of us. Does this motor use/lose any antifreeze? By all the rules you have three dead jugs, yep it will miss and use oil.

 

Yeah, it's highly likely it is simply "New Motor" time, and I have one hanging on the engine stand.... but, it's a used motor, unknown condition, aside from 150K miles, and "Ran good when pulled". The guy I got it from need a trans, bought a whole parts truck that had lower mileage, so just swapped both. I would *like* to coax a few more miles out of my current engine, to give me some time to at least freshen the donor motor before installing it.... Might have to just bite the bullet, slam it in there, go thru mine, and then swap them again.

Are we having fun Yet?

 

Why not pull the heads off the new/used motor, check them for cracks if none are found clean them and install them on your current motor. Don't rebuild them just install them. I had one motor that was down to 60 swapped the heads and it came back up to 135.

This would buy you sometime to get the other block freshened up and time to find new heads for it. I know it is a lot of work for you but that's about all I can suggest if you want to make it last longer. I have done the heads thing a few times now and best time for me was close to 12 hrs and everything was as bench prepped as much as possible.

Edit: It takes longer to swap the heads than to swap motors so well kinda hard to say.

 

I did this on my aunts yota. She got another year out of it before it finally gave up going down the interstate

 

Also much cheaper to just swap motors..... that was also the original purpose for purchasing the motor..... I should just do it......

 

I would offer to help but I am just to far away.

 

I was just thinkin' "You need a vacation!" Come on down!

 

^^^ Agreed 100%

Just after the new year if things are taken care of by then, we might just do that. 33 hrs to drive one way, so looking a flight costs see what it's all about. What is your closets airport I am getting Detroit?

 

Yeah, Detroit, or Toledo, OH. Although, I think any flights going to Toledo go thru DTW in any event.