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High Emissions

My 1993 Nissan Sentra with 110,000 miles flunked the smog check. I had a tune-up and replaced the distributor cap and air filter. It passed the next test but the emissions were still high. Should i have driven the car for a period after the work was done? Jiffy Lube offers s cheap crud cleaning service. Would this help? What ele should I do?

You will have to work a little bit by telling what PPM readings were and at what RPMs. Yes, all of them. Which engine and HP?

What state are you in? What kind of test? (was your car run on rollers)

Failure of the HC and/or CO levels suggest different causes than failure of the NOx levels, and the amounts offer more clues. In addition, of it was run n a dynamometer (Caddyman’s “rollers”) then the RPMs at which it failed may help to isolate the problem.

More info please. And also the maintenance history and whether it uses oil or not would help.

Oh, I almost forgot my most important point: AVOID JIFFY LUBE!!!
Find a reputable independent owner-operated shop.

I don’t know the horsepower. It is the XE model if that helps. The PPM measurements were the following: 1839 RPM Max 720 AVE 150 Meas 633 15MPH
2016 774 136 403 25MPH

I’m sorry, but I can’t make hide nor hair of your readings post. What numbers are what?

You should have three readings,
unburned hydrocarbons (in parts per million, PPM)
oxides of nitrogen (NOx, in PPM)
carbon monoxide (may be represented as a percentage)

I’ve posted a link that should help explain
Post the individual readings and we can better help.