exhaust problem

I was given a 1991 ford escort pony. It needed a tune-up really bad, but otherwise was ok.
So we do the tune-up, including replacing the oil filter and the fuel filter and (of course) changed the oil, but now the car spews out blue smoke from the tailpipe when the car is first started (it stops after the car has run for about 5 minutes) The car passed an emission test in January of this year. In addition, there is no evidence of an oil leak.
Do I need to change the pcv valve? A neighbor suggested an oil detergent, but what is that and should I use it on this car which might have high milage. (it was 58,000 when I got the car, but it is reconditioned so I really don't know how that affects the odometer)? I should say the car SOUNDS great, no knocking or pinging, starts up in any weather and runs well (but I know I'm losing gas milage).
What do you think I should do?:dunno:

I know you just changed your oil... but crack the plug open and see if any water comes out. Also... after the engine has been running, pull out your oil dipstick and see if the oil is foamy at all.
Either of these is an indication of water/coolant being where it shouldn't be and can be a result of either a bad head gasket or cracked head.

Try this test also:

On the last trip of the day, before shutting down the engine ... pull the PCV valve and hose out of the valve cover. Hopefully the engine will still run. Let the engine continue to run for several minutes before shutting down for the night.

Next morning, start the engine (if it will start) without replugging the valve. After start-up, reinsert the valve.

Was the smoke lessened? If so, the PCV valve may need replacement .. or.. there is too much oil in the crankcase ... or.. the air filter is plugged up.

I think that when valve guide seals wear out then oil can drip into the cylinders after shutdown so that it will smoke when you first start it up.

You are looking for oil burning when possibly the engine is dumping too much fuel in the engine. I say that because of the poor gas mileage.

You can shake the PCV and if it rattles, it is okay. Detergent oil is just that. It has an additive to help keep deposits from forming.

Usually I will run a thicker oil in an older engine. That being a 4 cyl....20W50 is fine.

Like Tumbleweed said, worn valve seals will do what you describe, but it won't worsen your gas mileage.

Have you changed the plugs?? Was one plug worse than the others??

Fords are bad about the EGR valve clogging up causing it to smoke also on start up. It's the flying saucer looking thing under the TPS where air enters the throttle body. Remove it and clean the carbon build up out of it.

Another thing is to check for trouble codes. Don't have a code reader, go to Auto Zone, O'Reilly's or Advance Auto Parts and they will pull the codes for free and you can replace any bad sensors. My Ranger had a bad ACT sensor and would smoke on start up then clear up.

I've got some hose on my intake disconnected, my EGR plugged, and when I pull off my oil cap my engine dies.

My car doesn't smoke.

The disconnected hose is the one that connects to the air filter housing, what is it?

What's causing my car to die when I pull the oil cap off? It also stumbles when I check the oil while it's running.

EDIT-I'll make my own thread.