1993 Q45 Shaking

[gbxk86a]

About six months ago, my 93 Q45 ran fine that morning, but in the afternoon after it was parked under the hot sun for eight hours, it suddenly started shaking and ran sluggish. The car has 130,000 miles. Spark plugs, trans flush, fuel filter and tuneup (along with belts and other fluid changes) were done at 110,000 miles by the dealer. Injectors are still the orginial. Sensors, wire harnesses, and emission equipment were all orginal. I put in gas treatment and asked the dealer to do an fuel injection cleaning (they claimed their process includes valve and combustion chamber). The car ran better for about one month. Then happened again. Put in a bottle of fuel treatment yesterday, and the car seemed to run better (less shaking and better acceleration). The car always idles steadily with a minimum of about 600 rpm. I am contemplating to retire the car, but want to ask if there are things that are relatively minor I can try or test first before donating the car? My daughter is driving the car around college campus. She has some attachment to the car as she grew up with it.

[Q45tech]

By 130,000 miles I had spend around $20,000 roughly 15 cents per mile to return my 90 Q to like brand new condition. The first 100k cost $8,000 and the next 30k cost $12,000.

Now there were significant reliability upgrades from 90 to 93 but a 14 year old car is a 14 year old car.

I don't know what your level of perfection is?

The car ran better for about one month. Then happened again. Put in a bottle of fuel treatment yesterday, and the car seemed to run better (less shaking and better acceleration).

http://www.deq.state.va.us/tanks/ethnfo.html

If a can of BG44k improves the smoothness after 100 miles and the problem returns say after 500 miles you have injector problems from the ethanol in fuel [water corrosion].

I would check fuel pressure as the ethanol may have corroded the fuel pump [in any case 14 years is probably time to change the pump anyway] I've never seen one that lasted 14 years..........most fail from 100k-150k and 10 years.

What color is it [I'm always looking for Gray on Gray].

[gbxk86a]

It is beige.

Looking at your address, are you the infamous T3?

[Q45tech]

Virginia went Ethanol in May/June 2006 about time for any associated problems to show up.

Also many refineiners are now switching over to winter blend which might create another WAVE of problems?

Q45tech and T3 are associated.

[gbxk86a]

I always use premium fuel from Exxon, Mobil, Shell and Amoco. I may have used Costco or Sheetz fuel two or three times in the car's life.

I have avoided using off-brand fuel and avoided ethanol whenever I noticed it. However, lately, it seems like a lot of stations including the major brands use 10% ethanol.

The car still have good interior (very clean carpet but slightly scratched surface scattered on a 2 inch spot on the front pasenger seat). The car is still shiny on the outside. Tires and brakes should have another 20K to go. However, how does one justify putting in $13,000 on a car when it is only worth $4000 in excellent condition in the market. Not that I am trying to sell it (I have traded in cars three or four times but have never sold any car), but I am trying to rationize any decision based on economics.

I believe that the fuel pump (which I actually suspected), fuel injectors (if not now, very soon later) and the timing chain guides need to be replaced. I know also my front ends need to be fixed - upper struts for sure. Rear speaker amplifier boards need to be repaired/cleaned (intermittent squeal). This is about $5000 repair?

BTW, one more question. At around 11.5K miles, I started to notice a resonance of some kind at 40 mph. Balance tires and front end alignment did not help at all. Do you know which component was loose causing this resonance? I recalled that I read other people had similar experience in their Q's of that vintage.

Do you know of any good Infiniti servicing facility having as good a reputation as T3 near Northern Virginia?

[Q45tech]

You spend the money along the way each year in maintenance and replacements things don't have to fail totally before you replace them.

Shocks, tension rods, upper links, engine mounts, transmission mounts, wheel bearings, suspension parts, tires, brake rotors and pads, spark plugs, plenum hoses, knock sensors, belts, fuel pumps, sunroofs, window regulators.

The problem or solution is you drove abnormally low miles in the 13 years whereas I drove the same 130k in 8 years 10,000 miles per year vs my 16,250 miles per year.

You waited too long to fix the car.

Never understood what how much a car is worth has to do with how much it cost to fix it.....................as long as you can prorate $3,000 per year and get enough miles per year out of it.

Of course it costs more per year to keep repaired than it can be resold for, such is the life of a sunk asset [paid for]------ free ride except for repairs.Low liability insurance, low tag and annual taxes.

What kind of vehicle can one drive for $250 per month [mainteance included]

[Q45tech]

am trying to rationize any decision based on economics.

PROBABLY TOO LATE, repairs and maintenance have a way of creeeping up on people who don't keep seperate accounts for each car.

For those that don't put away the set $250 per month from day one and let it build [except for paying as you go]..............then you would have $39,000* less expenses in the maintenance account] which you use to repair or pay to purchase a new car.

* 13 years x $250 per month minus expense for maintenance and repair.

Most people just accept that in 13 years the car depreciated $40,000 and call it a day....................in the end spending the mainteance money won't make the 13 year old car worth much more to somebody else.

It just puts off the day of reconning when you have to find another car.

It really depends on how much you LIKE/LOVE a car and what replacement choices you can find.

[gbxk86a]

Your points well taken.However, I did have all the 30,000 and 60,000 mile preventive maintenance done by the dealer(s). I was just lucky that not that many things need to be replaced, as determined by them. If I add up, I actually may have spent $8000 on the car so far. I did have an extended warranty with the first seven years. Without that warranty, the cost actually may have been $9500. Of course, I am including filters, belts, tires, brakes, batteries, oil changes, transmission oil changes, coolant change etc, and other consumables.

I think at this time, the biggest factor is "how much you love the car." My daughter really likes to keep the car. Right now, I let her drive the 2001 QX4 instead concerning the Q may break down completely at any time. She kept on telling me she would rather have the Q45.

Have you heard of any reputable facility familiar with Infiniti in our area?