Oil change now miss fire

C

Co-Runner

New member
Hello all,
so quick background. 1999 t4r auto with rebuilt 3.4L bored .40 0ver.
just had my motor rebuilt, put it in the truck and ran 5w-30 oil in it for the break in period. noticed I had a oil leek on the oil cooler, no big deal bought a new gasket for it and changed the gasket while I was draining the oil. so I got all of that back together with a new oil filter. put 10w-30 oil in it.

Went to turn it on and it ran really rough. Almost like a misfire. the motor shakes and runs terrible. then it will shut off. It will crank for a good 10 seconds before it fires up and runs rough again.

Am wrong to think I have a rod knock? Or if a ground got oil soaked could it run rough? I didn't mess with any of the plug wires. and I have no CEL
Side note. my Cheap OBD reader wont connect. not sure if I have a ECU problem or the blutooth reader decided to fail.

any help would be great!
 
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The only way I could see the oil change having anything to do with the rough idle would be if you knocked a vacuum line lose, or an electrical connector. It's very likely a coincidence that the two happened at the same time, but I'd take a look at those two things first.

You might try disconnecting the battery for a few minutes to reset the ECU, and then try and connect the OBD reader to it. A bad ground on the engine might cause your symptoms, but I wouldn't think it would prevent the reader from connecting to the ECU because they're sharing a common ground in the port.
 
jeremyc74 said:
The only way I could see the oil change having anything to do with the rough idle would be if you knocked a vacuum line lose, or an electrical connector. It's very likely a coincidence that the two happened at the same time, but I'd take a look at those two things first.

You might try disconnecting the battery for a few minutes to reset the ECU, and then try and connect the OBD reader to it. A bad ground on the engine might cause your symptoms, but I wouldn't think it would prevent the reader from connecting to the ECU because they're sharing a common ground in the port.
Click to expand...

See this is what has me stumped... I went through and checked all my vac lines and plug wires. sprayed the ground under the oil filter down with brake clean and cleaned up the rest of the oil. Then pulled the negative battery cable for 30 minutes. drained the 10w out and put new 5w in it for sh**s and giggles. it sounded better on start up but still runs rough and like its miss firing. I believe I hear some metal on metal in side the block. but I could be me going into worst case scenario mode.
ill upload a video so every one can see what I mean
as far as the OBD reader I think its just fubar
thanks for your help!
 
Did you notice the oil leak at the 1st oil change? How many miles did you do with the oil leak?
Any chance you ran the truck with low oil level?
 
Sounds like lifters to me. They sound oil starved. .40 over is a lot. Did you have them sleeved? Is your motor under warranty? I would hope so if someone did the rebuild. Your 5-30 should have been sufficient for 1500 miles before changing it. I would bring it back.
 
Sorry for the wait. I was out of town this weekend.
So I'm thinking something may have come loose when I put oil into it. I had the father in law come take a look at it. We both determined that the sound is to inconsistent for a knock. More like a nut or piece of metal has fallen into the cylinder. It also sounds like metal on metal. Plus the second time I drained the oil it looked like a dang gold pan. The drain pan was full of metal shavings.
Looks as if I'm pulling it for the 4th time. :frusty::frusty:
thanks for your help guys! ill keep you all posted with what I find.

pulled the engine code (stupid OBD reader decided to work) #3 and #4 cylinder are miss firing.
 
Rock_Rat said:
Sounds like lifters to me. They sound oil starved. .40 over is a lot. Did you have them sleeved? Is your motor under warranty? I would hope so if someone did the rebuild. Your 5-30 should have been sufficient for 1500 miles before changing it. I would bring it back.
Click to expand...

Yeah .40 over was a lot more then what I wanted. no sleeve, just .40 pistons and rings. Not really as the guy that did it is a "back yard" builder.
I'm going to at least get my money back from him. or he's getting a 3.4L thrown through the front window of his house lol
 
nissanh said:
Did you notice the oil leak at the 1st oil change? How many miles did you do with the oil leak?
Any chance you ran the truck with low oil level?
Click to expand...

I noticed the oil leak the day after the install. I kept a close eye on it. and it only fell half a court low. i pinched the seal on the oil cooler when i put it back on. but when it warmed up it did stop. it was just weird it had problems right after i did the oil change. that's why I'm thinking something has come loose
 
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