Tire Pressure

[TexRodeo]

Ya know One thing I never quite understood is why a car of the J30's size and weight, Tipping the scales at nearly 3600lbs is rated on the Tire Placard in the Center Console Lid as it only requiring 29 PSI of air in the 215/60 R15 94H Standard Size Tires. I would think it should need a lil more air, Is there a reason for this?

[ezb57e]

Better/softer ride.
They weren't in a MPG panic back then.
Id sure run them higher.
Just keep an eye out for signs of center tire wear.

[TexRodeo]

Oh OK, I understand. I figured that it had something to do with the Handling and ride characteristics. But being what Times are and where Gas Prices are for the required Premium Gas. What would be the Optimum tire pressure to run and being as poor as I am, that would not only help improve the Gas Mileage and not to prematurely Damage the tires...?

Oh BTW I still have my original Doughnut or Temp Spare Tire up in the Attic. But I have purchased a Full-Size Matching Infiniti Rim from the local salvage yard and a New Tire for to use for the Spare. I have always hated the Temp Tires, They always ride so Horribly.

[ezb57e]

I'd run 32-33 psi and keep an eye on the wear.

[TexRodeo]

OK, I shall Give that a Shot.

I recently, had some issues with some hesitation and sputtering at lower RPMs below 2000.

I have noted that My gas mileage seemed to drastically improve after switching the Autolite APP3924 Platinum Plugs out for the correct NGK PFR5G-11 Laser Cut Double Platinum Plugs at nearly $14/plug which got a lil pricey for the 6, But that's what the factory service/shop book in the trunk calls for. I can honestly say that I have seen some strange spark plugs in my day, But I had never seen Spark plugs like that with the Fine Point electrodes. According to the AutoZone employee, that its for precision firing and of course that this Z-Car (VG30DE) engine requires in order to operate optimally with the best performance and gas mileage. Of course my ears perked up, Hell Anything that saves gas gets my attention with this car.

Another thing that really seemed to help, And I personally think was the main culprit in this hesitation escapade; was to thoroughly clean the MAF (Mass Airflow Sensor) with a can of CRC Mass Air Flow Sensor Cleaner at $8 for the 16 oz. can...Which beats approximately $200 for a replacement Sensor. Of course I used the entire spray can to clean my sensor.

Although It wasn't instantaneous after changing the plugs out and cleaning the MAF sensor for the engine to smooth back up. I had to let her idle awhile and drive her some for her to gradually smooth up to actually better than normal operation.

But thanks for the information on the tire pressure, again I will give that a shot. Hey, anything to save a few dollars on the Premium ONLY Gas, I am all up for.

[goody90q45]

The recommendation from the Q45 forum is to run at 80% of the maximum pressure rating. You can find the max pressure on the tire sidewall. A lot of passenger car tires have a 40 psi max and 80% of that is 32 psi.

[TexRodeo]

OK, Thanks my friends I appreciate that. I will give 32 PSI/each one these tires a try. I guess that wouldn't make a bit of difference that I am running the stock 15X6.5, 7-Double Spoke, 5x4.5 bolt pattern, Base model OEM J30 Alloy Rims on my 1993 J30 with the standard or recommended size tires, right?

BTW " goody90q45", Very Nice Q...!!! My J is also a Pearl White color (WKO/White Satin Pearlglow) with the (Q Interior Code which is Eggshell (Cream) and Medium Brown).

[J30inthe sun]

The psi rating is based on the engineering of the suspension by the factory. For optimal ride the engineers set that rating for the tires at 29 psi to work in conjunction with the suspension based on design.

[TexRodeo]

Ahhh, It just seemed Like such a low amount for the Size and weight of the car was what I was questioning, "J30inthesun". Hence why I posed the question

I was just wondering if it was something that was a necessity. But If It will adversely affect the suspension and handling, Maybe I Shouldn't attempt it. Mechanic I am not, I just know what I know and attempt what I do out of financial necessity.

I do know this car is very pricey on parts and repairs...Besides I have a rather large fear that parts will become much more scarce as time progresses. I also know that the J30 can be somewhat picky on certain things, That being said, I wouldn't want to take too many unnecessary risks that could cost me much more later down the road because of one wrong decision or following the wrong piece of advice on something so minor as tire pressure.

[ezb57e]

Try them at 32. You'll like it.