any auto mechanics?

[ginman999]

For any auto mechanic out there. What could cause a motor to bog down intermittently. Sometimes from idle I'll give it about half throttle and the rpms come up very slowly. I have done the usual stuff, rotor, cap, plugs and wires, fuel filter, PCV. Its a 4 cylinder EFI with 99K miles.

[Pogo]

Could be the catalytic converter. In fact, that would be my first guess. But, of course many other things could be the cause also. :p

[ginman999]

Cant be the Cat. Its been neutered

[elder]

fuel pump? (You already checked the fuel filter. )
Water in the gas?
Dirty injectors?


I've had an old Ford do similar things, turned out to be the ignition module.

[Noah Zark]

Could be going lean. I would have the fuel pressure checked to see if it is in specification range. Also check for vacuum leaks.

Noah

[hootch]

Could be the mass air sensor If it is not the fuel filter being clogged and you already checked the obvius Cap, rotor plugs and wires, air filter, vacuum leaks ect.

[New b 2 AKs]

What year/make/model is this motor in? I would also suspect the mass airflow sensor, although the other suggestions are just as likely. Also, you may want to check out the throtle position sensor. It too can cause the problems you described.

[63DH8]

If the MAF is bad, it'll act like a choke wasn't working right. You'll have to play with the gas pedal to keep it running. Of course, if it has a Mass Air Sensor, there's no choke. Does it run okay until the pedal gets to a certain point, then falls flat on it's face, then runs okay when you press the gas pedal further? If so, your throttle position sensor is bad. It's located at the end of the throttle cable in the engine compartment. Unplug the wires and put one multimeter (set for ohms) lead on the center terminal, the other lead on one of the outer terminals. Now slowly rotate the sensor's arm or where the throttle cable links to the sensor. If the reading on the meter slowly goes up, then drops suddenly, then continues up, you have a bad sensor. If the meter slowly rises all the way as you turn the shaft, move the multimeter lead to the other outer terminal and do the same thing. If the meter rises smoothly all the way again, the sensor is good.

Other than that, it sounds like you may have water in your tank. If you didn't keep your gas tank filled over the winter, it's a common problem.