Truck runs rough once warmed up.

Back when I was doing the Baja500 before it was cool.

 

All mentioned high speed driving in this thread took place on a closed course, in Mexico.

 

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Of coarse!

 

Mine was on the autobahn

 

Pulled the plugs, sparyed them down with brake parts cleaner, put them back in. Truck runs 200x worse than before. Misfiring like crazy and now is throwing codes. God dammit what the hell man

 

What codes you got?

 

P0300,303,305. Pretty much the exact same codes before i took it in a few weeks ago.

 

Have you swapped coils around to see if the code follows?

 

I still think it's something other than your spark plugs.

 

It very well could be. Will the 303 and 305 also cause a 300 to trigger?

 

Cylinder numbers 8's coil is cracked. No misfire there according to the computer. I still think its my plugs or the anti seize on the spark plug threads inside the engine block. I have not tried swapping the coils. But its the same exact problem as last time and last time the mechanic cleaned the plugs and it was all good for a couple weeks after that. It started running rough at 1,000 rpms over the weekend so i put new plugs in, same problem again so i took them out and sprayed them with brake cleaner, put them back in and it ran like complete crap. This morning it runs a little better but still bad.

 

Just confuses me how the truck was running decently alright, then i pull the plugs and clean them, then it runs like poopoo

 

Cracked coil pack. Probably the original ones at 19 years old? I just can't see how you got that much anti-seize down there to keep doing this. I would be considering new coil packs.

Big Gurl has them on sale right now.

$55 Denso 6731303 Ignition Coil , Gray

https://www.amazon.com/dp/B002Y37M0...olid=1ZCWOVJG07GWJ&psc=1&ref_=lv_ov_lig_dp_it

 

Ok, will do. Maybe the brake parts cleaner messed with them. They look nice and clean but the top of the Lshaped thing thats at the very end is white and ashyish looking. Its just that they are less than a week old. But maybe i messed them up. I'm getting no other codes other than the ones stated above. Another thing to note, on cylinder 3, the spring in my coil is loose and can be heard rattling around, not sure if thats an issue. Cylinder 3 and 5 are misfiring. Cylinder 5 has a newish coil that the orginal owner replaced a few years ago.i will swap coils around to see if the code follows

 

Damn! Thanks. Those are nice and cheap. Im just hesitant cause i truly believe the coils are fine. I will swap them around and check

 

Thanks for the help guys. The tricky thing is, yesterday it ran so rough the dummy light started blinking and gave me the codes. I cleared the codes and came back an hour later. It still ran rough but not AS bad, but didnt give me any codes.. smh

 

When you were doing all this , did you maybe inadvertently knock a vacuum line loose ?

 

I checked and no i did not

 

Those Denso Coils are the fo shizzle Puckshizzle.

 

Why are they so cheap? Usually theyre like 100 bucks?!?

 

I bought mine almost 2 years ago through Densos Big Gurrl Store for $54 each. Bought 8 total.

You can verify through Denso site and they will offer links to sellers for around that price if they are an online store. Prime shipping saves me and delivery in 2 days!

 

I had the same thing happen to me a few weeks after I bought my truck but it wasn't after it warmed up, it would happen right away. multiple cylinder misfire related to ignition coils. I changed plugs and did a few diagnostic tests, swapped coils from the side of the engine that wasn't misfiring, didn't change my codes or the rough idle. Had it towed to a shop and 6 days later they found the corroded ground wire (I think it was near the fire wall) that was causing the problem. Cost me $500 for them to find it and another $100 for the tow. Hopefully you've got the same issue and I can save you the head ache I went through

 

You are correct that there is a ground wire back there. If you reach over the pass side of engine bay and reach behind/between the engine and firewall with left hand, it is located right there. Its a thick wire that bolts onto the block with a 10mm bolt. The other ground is over by the battery.

 

yeah, it wasn't something I was looking for at the time. I checked my grounds off the battery, fuses and did a few other things but didn't think to check behind the block. It's the ground for the ignition system as well (or that's how it was explained to me by the mechanic who fixed it) .. and given I was only having a 4 cylinder misfire (drivers side of the engine) I would say the other 4 cylinders likely have a ground back there too on the passenger side

 

Checked that, i even put my 10mm on it to just make sure it was tight, thanks though!

 

So you replaced all 8 for preventative maintenance? Thats a lot of money lmao

 

5 had cracks. When I researched these, many 4.7L Land Cruiser guys were replacing all of theirs. Their engines came out in 1998. Some went cheap Chinese and they failed only to return to these Denso Originals at a good price.

Only reason I replaced them is, supposedly, the spark will shoot through the coil cracks into the tube or travel over to the next tube resulting in misfires.

I replaced one coil prior when she went really bad and allowed me to limp home. Only time my truck has ever had a problem. She was running rough! Won’t allow this to happen again.