97 QX4 missing at idle (15"BTC not even close)

[Mrelcocko]

Here's my problem guys. Back a few months ago me being the dumbass I am I sat a cup of coffee on top of my motor and knocked it over. Then immediately tried to start it. Wouldn't start at first and then when it did it ran like crap. After replacing everything known to man I finally got it running fairly decent except the fact it misses at idle. MIL comes on and will flash if setting at a red light and stop when I accelerate. If I drive it a few cycles where I don't get caught by any red lights the MIL will turn itself off but come back on after sitting and idleling for a few secs sitting at a red light. Run the codes and getting the dreaded P0300 along with p0325. Went through the procedures in the fsm and everything checks out except the timing is way off by the timing light. Looking down from the front of the engine holding my timing light the pointer that's on the block is way right of the 5 marks. In other words if I took another five marks and sat them beside the ones already on the crank pulley rom tje factory that's where my pointer is. I'm trying to explain this the best way I can. If I floor the car it has power and doesn't seem to be out of time. It starts up every time no problem at all. This all started when I spilt the coffee. Can we say dumbass? Please help peeps. The timing belt was replaced by the previous owner at 210000, it now has 246000 on it. I'm a shade tree mechanic and know a few things but don't know where to start.

 

Sent from my SM-S337TL using Tapatalk

[Slartibartfast]

Start by finding a better place to put your coffee cup (I say, having balanced Coke cans on my intake quite a few times).

 

People splash mud on these motors all the time without causing misfire issues, so a little coffee shouldn't have screwed it up like that. The weird timing is probably the ECU realizing there's something wrong and dialing back to play it safe. Running well at speed but poorly at idle sounds like a vacuum issue to me. Perhaps the cup hit something on its way down? Busted off a vac line?

 

I'd also inspect your ignition components (cap/rotor/wires/plugs/coil) and anything else that was in the coffee's path for any obvious residue. I don't know if a glob of coffee creamer schmoo down a spark plug hole would be enough to cause a misfire, but I can't imagine it would help anything either.

[onespiritbrain]

I had a frontier that missed at idle. Mine was caused by an invisible pin hole in one spark wire. I finally found it by slowly dragging the end of a screw driver across every inch of every spark wire in pitch black darkness.. one little spot shot sparks out...

 

Did you already replace the wires?

 

Also, I got water and mud down into the spark plug holes on my JR50 the first time I got stuck and one of the cylinders started misfiring and didn't stop until I replaced the plugs/wires and cleaned the area.

 

Sent from my iPhone using Tapatalk

Edited September 30, 2017 by onespiritbrain

[Mrelcocko]

Since I posted this it hasn't thrown an MIL. Even when I'm stopped sitting at a red light it hasn't come on. Very weird. I have noticed what sounds like valves rattling during accelerating that wasn't there before. I checked the timing which is off but now no MIL. If the computer isn't throwing any codes does that means everything is good? I'm no Einstein but usually if there's a problem with the engine/vehicle wouldn't the computer throw a check engine light?

 

Sent from my SM-S337TL using Tapatalk

[Slartibartfast]

If the computer knew everything, diagnosing engines would be easy!

 

Is the timing advanced or retarded? If it's advanced too far, you might be hearing pinging rather than valve noise. No idea how coffee would've changed your timing but if nothing else is obviously wrong, you might try setting the timing back to 15° (with the engine warmed up) and see if that makes it happier.