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Jake, Nissan Technician
Category: Nissan
Satisfied Customers: 3997
Experience:  Experienced collision repair technician, Pulaski Tech graduate and DSM hobbyist.
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Xterra: I have 04 xterra v6 2wd. Has a miss in the engine only

Customer Question

I have 04 xterra v6 2wd. Has a miss in the engine only when started cold. Everything on ignition system has been changed and helped but not cured problem. Only code is knock sensor high voltage on code scanner. I know timing is to be a 10 degrees and that the knock sensor retards timing. Can I set timing to 11 or 12 and then if knock sensor retards timing it will be around 10 dergress? It's non sc
Submitted: 2 years ago.
Category: Nissan
Expert:  Jake replied 2 years ago.
Hi there, thanks for your question.
If it ONLY misses on a cold engine that has been sitting then it's very possible you could have a head gasket leak into the cylinders or a valve cover leaking into the plug boot.
Have you checked this?
Customer: replied 2 years ago.
I have sprayed carb cleaner to look for a intake leak or vacuum leak with none found. The radiator fluid is green and doesn't bubble while idling
Customer: replied 2 years ago.
What about bumping up the timing a bit to compensate for bad knock understanding is on non sc and na engines it really isn't worth replacing on its on
Expert:  Jake replied 2 years ago.
I was talking about looking for oil or coolant intrusion in the cylinders. This would be from a small leak.
Changing ignition timing is not going to do anything for the knock sensor code. The only way to rid that is likely to replace the knock sensor, which in my opinion would be a waste of time and money. These engines were notorious for failing knock sensors and they have zero effect really on how the engine runs.
Customer: replied 2 years ago.
now there's no coolant or oil around plugs
Expert:  Jake replied 2 years ago.
Aside from the plug side, you can have leakage into the cylinders. you would have to remove the plugs after the engine has been sitting to see if fluid was in the cylinders. Fluid could come from a leaky injector or head gasket. The only thing is that USUALLY when that's the case you will get an occasional misfire code to a specific cylinder that has the leak. So that very well may NOT be the case for you, but it's still something to consider.
The other thing we see from time to time causing a miss at start of a cold engine is the catalytic convertor. Especially is the manifold is cracked or anything causing excessive condensation on morning start up.
Without any other codes at this time and no symptoms when the engine is warm. considering you have checked the others I mentioned. This would be the place to check next.
Customer: replied 2 years ago.
It has a exhaust leak for sure. So that could be causing condensation to build up in the cats to make it miss till it gets hot? If that's the case then new exhaust would fix the problem then right.
Customer: replied 2 years ago.
Is that intake man or exhaust you are referring too
Expert:  Jake replied 2 years ago.
The exhaust, not the intake.
Customer: replied 2 years ago.
The passenger side exhaust has cracks in it. Think that's what's causing it? It's kinda white around where they are
Expert:  Jake replied 2 years ago.
That certainly could be the issue of it only happens on cold starts.
Customer: replied 2 years ago.
How can I tell if it's the head gasket leaking if it's not missing with the oil? Trying some thermasteel to see if it stops it.
Customer: replied 2 years ago.
The heat shield was cracked too. Can I run without it
Expert:  Jake replied 2 years ago.
The only way to rule out a head gasket or valve seal is to a leak down test.
The other option for a small coolant leak in the HG is to pressurize the cooling system for an hour with the plugs removed and inspect the cylinder.
Customer: replied 2 years ago.
When setting the timing my truck won't crank after disconnected the tps. Do u think this could be the cause of the missing? Should I replace it
Expert:  Jake replied 2 years ago.
a NO CRANK condition would have nothing to do with a misfire. A NO CRANK is a problem in the starting circuit. You can have misfire issues from the TPS though yes. Generally though these electronic throttles are good about throwing codes.
Customer: replied 2 years ago.
Can u check injectors while they are still in the vehicle? Got the timing set with tps unplugged this time
Expert:  Jake replied 2 years ago.
you can check that they are functioning with a noid light or stethoscope. you can check for a leaking injector with a fuel pressure gauge and pinching the feed line to watch for pressure bleed.
Customer: replied 2 years ago.
Could the egr valve possibly be causing this by sticking from carbon build up? Can u check it without removing it or do u need to remove it
Expert:  Jake replied 2 years ago.
EGR valves sticking only cause loping or missing at idle. They would have zero effect when driving.
Expert:  Jake replied 2 years ago.
If you need further help please let me know.
If not please be sure to leave a kind rating.