Despite a rosier employment picture, high fuel and oil prices coupled with a still-sluggish home building market are keeping economists guessing as to the true health of the U.S. economy – providing yet more uncertainty for freight volumes.

Though the U.S. economy added 233,000 private sector jobs last month, according to the U.S. Dept. of Labor, the unemployment rate remained at 8.3%.

And though employment trends are on an increasingly positive arc – with the Conference Board’s employment trends index (ETI) increasing 1.38% in February over January, suggesting that rapid job growth is likely to continue in the next several months despite modest economic growth – high oil and fuel prices are adding renewed downward pressure on the economy as a whole.

According to the latest figures from the Energy Information Administration (EIA), U.S. average diesel prices climbed another four cents over the last week to reach $4.123/gal.. Diesel prices are up seven cents per gallon over the last two weeks and are nearly 22 cents per gallon higher than at the same time last year, the agency pointed out.

The EIA added that U.S. average gasoline prices jumped nearly four cents a gallon as well to $3.829. Gasoline is now 10 cents per gallon higher compared to two weeks ago and up 26 cents per gallon compared to the same time period in 2011, the agency noted.

Those price spikes dovetail with a much tighter – and more expensive – supply of oil, EIA said. “Oil prices have risen since the beginning of the year and are currently at a high level, [with] global liquid fuels consumption at historically high levels,” the agency noted.

“Unusually cold weather in Europe contributed to tighter markets by increasing the demand for heating oil, particularly during February,” it added. “With respect to supply, the world has experienced a number of supply interruptions in the last two months, including production drops in South Sudan, Syria, Yemen, and the North Sea. Both the U.S.  and the European Union (EU) have acted to tighten sanctions against Iran … [and] there is some evidence that these measures may already be causing some adjustments in oil supply patterns”

Finally, spare crude oil production capacity, while estimated to be higher than during the 2003 to 2008 period, is quite modest by historical standards, EIA warned – especially when measured as a percentage of global oil production and considered in the context of current geopolitical uncertainties, including, but not limited to, the situation in Iran.

Those mixed indices are creating greater sluggishness in overall economic metrics. For example, the Ceridian-UCLA Pulse of Commerce Index (PCI) compiled by the UCLA Anderson School of Management and Ceridian Corp. increased only 0.7% in February – not enough to offset the 1.7% decline registered by the PCI in January.

The most recent three-month period from December to February is lower than the previous three months from September to November 2011 by 3.2% at an annualized rate, noted Ed Leamer, chief economist for the PCI and director of the UCLA Anderson Forecast – adding that even with the February increase, the PCI signals that the economy is much weaker than suggested by many other indicators.

“Specifically, the PCI suggests that the first quarter is shaping up very poorly,” he said in a statement. “The January 2012 PCI is 1.8% below October 2011 and the February 2012 PCI is 1.3% below November 2011. With those negatives already known, we will need the PCI to grow by over 4% from February to March just to allow the PCI to grow positively in the first quarter of 2012 compared with the last quarter of 2011. That has happened only once in the 157 months since January 1999, the month that the PCI data dates back to.”

In other words, the PCI indicates a very weak or even negative gross domestic product [GDP] growth rate in the first quarter of 2012, he explained. “That’s not a forecast,” Leamer stressed. “That is a word of caution regarding our currently exuberant state.”

The continuing weakness of the PCI perhaps is signaling that the recovery in home building has not yet taken hold, he added. Yet the recent improvement in building permits and housing starts may get building going again and trucking as well as it’s estimated that it takes 17 truckloads to build a home.

“If we get the saws and hammers going again, we will have a real recovery with much healthier job growth,” Leamer said.