Here we go again. Robert the non-mechanic recommends a non-Ford recommended viscosity motor oil which happens to be 5W-20 not 0W-30. The throttle body opens which allows air to enter the intake manifold BUT the non-mechanic he is has no clue what the function is of the air passing buy the Mass Air Flow Sensor BEFORE the air passes through the throttle body which triggers the ECM for the correct fuel flow through the injector nozzles.

A dirty IAC would only cause problems at idle and during deceleration. This could be many things, from a vacuum leak to a bad O2 sensor. First thing a mechanic would look at would be live scan data to see if the computer is adding or subtracting fuel. Right now you're just guessing. Get it to a shop and pay someone to get you an accurate diagnosis.

The service engine soon light is not mentioned here. If it were, I would say its possible you have a bad throttle position sensor. This sensor tells your onboard computer to richen up the injectors on acceleration.

FIRST OF ALL to say "STEP ON THE GAS" is a MISNOMER! All you do in reality is step on the AIR pedal! You have a dirty IDLE AIR CONTROL VALVE and THROTTLE BODY! The IACV ads MORE air as required by the O2 sensors! The use of BAD OIL clogs up sensors with sludge and tar and your engine is STARVING FOR MORE AIR! TAke $20-40 to ANY oil change place and get them CLEANED UP! The IACV on ALL Ford engines is removeable for cleaning up! Secure a can of AMSOI POWER FOAM and GUMOUT and do it YOURSELF! ALL FORDS just love MOBIL ONE 0W_30 oil and it GUARANTEES great running a\with NO clogged up sludge ball in lifters and tensioners! FORGET WAX BASED JUNK OILS and change it only ONCE a year! GOOD LUCK!!

I have a 2000 Ford Focus and the engine has been shaky. I do not consider my focus problem to be a “misfire” but that word could be used as part of the description, though I have replaced the spark plugs recently, along with the fuel filter & coils. My symptom is best described as this; hesitation, bog or stumble during light acceleration, a total loss of power/compression-> when at a stop and taking off. I can always recover from this (or prevent this) if I step harder on the gas pedal. Surging or bucking when cruising and barely applying the gas. I have never seen/felt a problem at highway speeds. Please note it only happens during light acceleration.

I don't know If its a failed failed DPFE, because the RPM's oscillates.

Thanks.