Hi all - I've found very helpful info in the past here and I'm hoping for more magic. I'll try to be brief.

2006 Xterra S, 93K miles, 6sp manual/V6. No problems to this point.

On two occasions this summer, I stupidly let my gas go very low, and after subsequent fill-ups, had a rough-running engine and blinking "Service Engine" light. On the last occasion (2 months after the first), the car actually sputtered and stalled out 3-4 times. Nissan service said that injectors were misfiring, but after two days of diagnostics, they couldn't say for sure why. They suggested perhaps a faulty O2 sensor, which would be $800 to replace. They also said that may not solve the problem.

My brother-in-law suggested water in the fuel line from letting the tank get so low, so we put a bottle of HEET in it, and the car ran like a champ thereafter. I added another bottle a couple days later, and it still ran great, even though the "S.E." light remained blinking.

But the performance remains less than I'm used to, and the engine makes a LOUD growl when I downshift to pass or go up hills. I've driven from NM to CT like this, and it's only gotten louder. Its usual power is lacking. I'm getting good mileage (22-24 mpg), though, and don't seem to be losing fuel. No fluid-y smells either. And the "S.E" light sometimes blinks, sometimes stays on, and sometimes goes off. No rhyme or reason.

I'm taking it to the Nissan dealer in Middletown, CT, tomorrow for another diagnostics run (at another $100). I'm thinking this is more than gunk in the fuel line. Any suggestions?

if the light is blinking do not drive it, you will cook a cat in a new york minute. What are the actual codes that were pulled?

Hi Granitex - according to the Nissan department in NM, the code is PO300 - multi-cylinder misfire.

When's the last time you had plugs wires cap and button? Also I would try a seafoam treatment

The 06 does not have plug wires, distributor cap or rotor.

It has a DIS ignition system, basically a coil over each plug triggered by the ECM when it becomes time to fire the spark plug.

I ended up dropping $1200 for catalytic converter repair and replacement! Car has run well since then, almost back to its old self. Then today, lo and behold, the Service Engine light came on yet again. I was driving in freeway traffic and felt a little shudder or poof or something, and then it seemed to run OK thereafter. Back to service tomorrow for yet another diagnostics run. GRRRRRRRRRRRRRRRRRRRRRRR!!!!!!!!!!!!!!!!!!!!!!!

Was told that the rear catalytic converter and the O2 sensor are having disagreements, which is why the check engine light came on. Would be a grand to replace rear converter, but that won't be happening. Stay tuned....

before you blow another grand, ask the service department if the removed the exhaust system from the cats back.

The reason for this is I had an X the toasted the cats, after the install of the new cats I still had runability issues, the thing was throwing all kinds of codes including air/Fuel ratio sensor codes.

The problem was the old cat material was building up infront of the secondary cat causing a bad back pressure issue tricking the o2 sensors .

ARGH!! Thanks NMT, for that suggestion. This is what drives me bats - is Nissan Service doing the job right the first time or not? Shouldn't these have been removed as a matter of course? I'm to the point where i don't trust these guys, and if I take the car over there or call again, it's gonna cost me. For dropping $1200 there, I was under the assumption that they were doing a thorough job. My mistake, evidently.

Whew.....venting over.

What do you mean by "old cat material?" I'm sorry to ask, but I'm a mechanics dumkopf.