rough idle code 41

[glgto]

need some help. kids explorer 91 eddie bauer all stock 4.0 about 115,000, all the sudden starts idling rough and throws a check engine light. checked codes via goose test code 41.
all vacuum lines look new and are tight, none cracked, cleaned maf, replace coil pak, plugs,wires. it definitely helped with power but rough idle still there seems to go away one warmed up. also cleaned the iac then cleared codes and took for drive blew it out (drove it like i stole it good ran fine the next day he drives it about five miles and it throws check engine again. assuming another 41 did not check yet. what am i missing? hard to fine good info on these older obd codes can it be a bad O2 sensor or a bad injector and the code is from other things compensating for it? he did say it smells like gas sometimes especially at idle. air filter is clean also
he is on a low budget what can i do? what can i check? not a auto mechanic but 30 year hvac tech so not totally incapable of testing

 

[2stroke]

This is a list of the trouble codes...
http://www.explorerforum.com/forums/showthread.php?t=160035

41
(R)
System lean - Fuel control

If you smell gas, you should not be driving it at all. Check for gas leaks. It could ignite at any moment.

 

[arco777]

A lot of times the MAF (mass airflow sensor) mounted on the intake ducting is the problem. It is very important to the PCM knowing how much air is coming in so that it can direct the right amount of fuel. Check that the sensor element of the MAF (the two heated wires inside the sensor housing) are not dirty.