Low Pressure in Cylinders 1 + 2, error reads lean bank 2 - Ranger-Forums - The Ultimate Ford Ranger Resource

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Old 10-17-2016
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Join Date: Oct 2016
Location: Seattle
Posts: 2
Low Pressure in Cylinders 1 + 2, error reads lean bank 2

2005 ford range v6 3L, 67k miles.

Two weeks ago my truck engine went into safety mode. I hadn't noticed a problem before then but that doesn't mean it wasn't there.

The engine error read multiple cylinder misfires.
When I pulled the spark plugs they looked hideous. I replaced the plugs, and checked the pressure. Cylinder 1 + 2 are at 90, the rest are at about 120. She will run again, idles at 700 rpm and runs rough, but if I get her to 1,200 rpm she sits back down and runs great. If she idles too long it goes into safety mode again reading the same error.

I replaced the wires and coil and now she is running better, still a little rough at idle and the error now reads 'lean bank 2'

when checking the pressure recently cylinder 2, and 3, appear to have a lot of gas on the spark plug.

Trying to consider what all of my potential options are, besides the head gasket, because I am in denial about that. Any thoughts would be appreciated.

Thank you.
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Old 10-18-2016
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Join Date: Jan 2014
Location: Vancouver, BC
Posts: 7,863
Welcome to the forum

2004 to 2006 Rangers with 3.0l engines had a problem with recessed exhaust valve seats.
TSB for that problem is here: Ford Technical Service Bulletin (TSB) 05-26-3

The exhaust valve seats were incorrect for the heads and over time would recess into the head causing a leak in the cylinder
Yes, Ford should pay for this fix but they won't

This reads like your problem, a machine shop can fix the heads but it is often less expensive and faster to just get new heads.

Low compression is of course a sign of this, a leak down test and listening at the tail pipe for exhaust leakage would confirm it.

3.0l Vulcan should be running at about 160+psi compression in all cylinders, 9.3:1 compression ratio.
Your 120psi could just be your gauge is reading low, but the 30psi less in other cylinders still indicates a problem.

The reason it will start to fire on all cylinders as RPMs increase is because with a cylinder leak the amount of time the piston spends on compression stroke is related to how much pressure can leak out.
At lower RPMs more pressure is lost so misfires would be more likely, as RPMs increase piston is moving faster so less time to lose pressure, and less likely to misfire
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Old 10-19-2016
Thread Starter
Join Date: Oct 2016
Location: Seattle
Posts: 2
...that definitely sounds like it could be my problem, and more expensive than I would like.

What kind of damage am I looking at to the engine from continued use? Can I buy a little time for a paycheck or two to come through or do I need to jump on this before it gets worse?

Thank you.
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