Newbie, and non-mechanic. When idling, the engine feels like it is starved for gas and is about to stall. If I give it gas it will generally pick up, although there are some rare times when the gas pedal is unresponsive. Check engine light came on; pulling codes 1-1-3, 2-1-2, and 2-2-1 in that order. Replaced plugs, wires, cap, rotor, fuel filter, and fuel pressure regulator. Two possible clues -- if I put a vice-grip at about 3/4 crimp onto the fuel return line coming out of the regulator, the car idles much better. I am also noticing that if I go through a puddle, I will usually get a good burst of steam from under the car as if the exhaust pipes are really hot. It feels a little like my VW vanagon did when the catalytic converter was plugged up. Any suggestions would be hugely appreciated.

 

Do you have a splash pan in place?

 

Thanks for taking the time to weigh in. I don't think I have a splash pan, if what that means is a protective cover between the engine compartment and the road. Nothing like that.

On a second front, constricting the return gas line was probably a bad idea . . . the brand new pressure regulator failed and some gas got down into the vacuum line. Wouldn't start at all. So I have replaced that and the car now starts but still idles extremely rough. Cleared all the codes and then rechecked. The new codes, in order of appearance are 2-3-1, 1-1-3, and 2-2-1.

 

The codes are kinda subjective, but those are pointing to "too lean at part load" and a problem with the O2 sensor.

I like to use a voltmeter because its non-intrusive. So I would start by measuring the o2 sensor voltage on the big green wire, while running and everything connected. It should swing quickly between .1 and .9VDC.

Then measure the voltage on the right side of fuse 4 while running, it should be at least ~13VDC.

Look for vacuum leaks.

 

Thank you as well for taking the time to weigh in. I swapped out the mass air flow meter and removed a fist-sized mouse-nest from my air filter and the car runs MUCH better. Better enough, in fact, that I wouldn't think there was a problem if not for the "check engine" light that is on. I have reset it, but it consistently comes back on after about 6 or 7 miles of driving.
Voltage at the green wire on the oxygen sensor when the car is running and fully warmed up is .07 to about .13 VDC. Voltage on the right side of fuse 4 while running is 13.79 VDC. My mechanic looked for vacuum leaks and says he didn't find any. I don't really know where or how to look for them, but I sure don't see anything obvious.
Codes from the on board diagnostics are the same, but in a different order now . . . 113, 221. 231.

 

See:
http://www.brickboard.com/FAQ/700-90...andDiagnostics

So either the O2 sensor is bad (or its not getting the 12v for the heated element) or it really is running lean - possible causes:
weak fuel pressure, old fuel filter
intake manifold gasket leak
injector seal leak
hole in the large hose between the AMM and throttle body (from rubbing against other stuff)

Your fuse 4 voltage is good.