175K Miles, how did it ever survive?

[Empty V]

So I recently rolled over 175,000 miles on my '01 QX4. I had noticed a significant loss in power about a month ago. What the truck was doing is in the higher RPM range the engine just didn't want to progress. So decided to start replacing parts that have been severely neglected.

First went the spark plugs which have never been replaced I was hoping that it was just a cylinder that wasn't firing, that wasn't it. Then went the 2 fan belts which also have never been replaced Then I took it to my transmission guy to diagnose because it seemed like a shifting issue. That wasn't it either so I took it to someone else to diagnose and he figured it out after 2 test drives.

Replace your fuel filters people it can be catastrophic if you don't! The fuel filter was so clogged up that it was throwing off the mass air flow sensor and the engine was basically being starved. If I let this problem go on any longer it could have destroyed the catalytic converters which would probably be about $1K to replace. Instead the new fuel filter and cleaning of the mass air flow sensor only cost me $107, wow.

Lesson learned, the old saying about an ounce of prevention really rings true. So every 30K miles I'm replacing my fuel filters, front pads and having everything else checked out. 60K miles the spark plugs and belts get replaced.

Billy

[Buzzman]

What engine does it have? (I can't remember when they switched to the 3.5.)

[Empty V]

What engine does it have? (I can't remember when they switched to the 3.5.)

Mine has the 3.5, I believe that 2001 was the first year of the 3.5 240bhp engine.

Billy

[bmlawless]

They went to the 3.5L in 2000.

On my truck, the manual says to replace the filter every 15k. The previous owner(s) had never replaced it and the fuel pump went out at 60k. My mechanic blamed the filter. Fortunately, my fuel pump whines when the filter starts to get clogged so it is easy to know when it needs to be changed. It needed to be changed at 15k and then I must have picked up a crappy load of gas because I had to change it again about 2k miles later.

Luckily it takes about 10 minutes to do.

[KoukiS14]

They went to the 3.5L in 2000.

Yup, for 2001 MY R50s.