1989 Mercury Sable i noticed my car hesitates while driving

1989 Mercury Sable i noticed my car hesitates while driving

Probable Causes of Engine Hesitating or Stumbling:

Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires

hi i wrote before an got some good advice i ve replaced every sensor i could find on my car didnt help, even did the air cleaner, plugs, pcv valve an hose connecting it ,still nothing fixed any bad hoses i could find put new air cleaner hose on the throttle body to the air clean plus new hose on the valve cover to air cleaner, still nothing i took it to a mechanic he put 2 more sensors on it that i missed one was the cooolant sensor the other was something to do with air on the back side of the manifold that had a plug to it any way he made the car able to run better but he claims not to be able to set the rpms says if he did with computer they would go back to where they are when u hook up the battery any way the car is some what driveable but still hesitates an has surges of power an i hear a back fire noise as i drove it im very low income but i need a car as i cant walk alot please help i need my car thank you an god bless

ok i got the back fire in the motor straight the air cleaner wasnt tighten down right but im still having the other problems i sure need help with this i think my rpms are screwing every thing up if i can get them straight maybe i can get some where with it any ideas. thank you god bless

Did you checked everything I've mentioned earlier these are your possiblities.

ive replaced the map sensor the TPsensor i replaced but put the old one back on i put new plugs in new pcv valve new air cleaner in new idle air control valve i ve never had a EGR valve on the car since i had it i dont have a MAS sensor either im told new hose for the pcv valve new air cleaner hose new hose from the air cleaner to the valve cover the coolent sensor was replaced an a sensor that plugs into the side of the maniflod it ran ok for a day then started hesitating an doing a surging thing it was making a popping sound but i found it was the air cleaner had come undone an was open thats ok now this mechanic i went to said he couldnt set the rpms because after he did it by the computer im assuming in the car when he hooked up the battery it would go back to the way it is im feeling the rpms are screwing this up or else driving the car with the kick down cable off the kick down cable is ok now what do u think thank you an god bless

Did he scanned the computer for code/s? Also computer might have to go thru relearning process due to disconnecting the battery

hi,

i talked to the mechanic i used to put the parts on he said he can do the code thing but for some reason didnt figure that when i had alittle money to fix it which really peeved me by the way when i get my debit card with the visa logo on it reactivated i will send u a donation thank you for ur help my income is such i can only do a few things each month thank you again. sincerely rebecca

hi again, i had my codes checked apparently they are ok every mechanic i take this car to is baffeled by it, seems every thing looks right codes every thing, they cant figure out why the Rpm are low an it hesitates,seems to have a hard time excelerating an surge at or below 35 mph, after 35 mph it drives fine thank you.rebecca god bless

Possible Causes of Engine Hesitation

Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires