hard start, rough idle

[robert1]

I have a 92 ranger 4.0L .It started acting like the coil pack was breaking down. I replaced the coil pack, no difference. I then changed plugs,wires,crank sensor,and throttle position sensor( had a crack). Changed fuel pump and filter, still the same.It is hard to start( especialy when cold) runs very rough, when you press the excellerator it bucks or stalls.Will not rev up past 4000. once in awhile the engine light will go out and it idles fine and has the power it should have, but this is very seldom the case. I am not sure if the temp sensor or cam sensor could cause this. Can anyone give me some direction.


Thanks,


Robert

 

[H311RzR]

Have you checked the Mass airflow senser? may be dirty/damaged.

 

[robert1]

Have you checked the Mass airflow senser? may be dirty/damaged.

No I haven't. Totally forgot about it. Will try today and let you know.

Thanks,

 

[robert1]

No I haven't. Totally forgot about it. Will try today and let you know.

Thanks,

Tried cleaning it , no differance , so replaced it , still the same. even when it is unplugged there is no change in the way it runs. Is it the wiring for the MAF sensor or is it unrelated?

 

[matticus420]

same problem with my truck
i would start it, it would jump to 1750 rpm then drop to to 500 then stall
i have to start my truck sometimes 3-5 before it stays on
i have changed the map sensor both o2 sensors the tps sensor fuel pump and fuel filter
and its still doing the same thing :[
the check engine light comes on every once in a while i dont want to take it to go get scanned because the light doesnt stay on all the time and i think if they scan my truck an the lights not on it would be a waste of $$
it also doesn't go past 4k rpm
every once an a while it will preform like it should but then quick goes away

my conclusion on my truck ive searched everywhere and i pretty sure my ECM is going out (it cant have gone out then my truck wouldnt stay on)
but havent had much time to check it out
they say if it smells like burnt wires or rotten fish it time for a new one

 

[LIMA BEAN]

Tried cleaning it , no differance , so replaced it , still the same. even when it is unplugged there is no change in the way it runs. Is it the wiring for the MAF sensor or is it unrelated?

Here is the wiring for it.

http://www.therangerstation.com/tech_library/CleanMAF.html

 

[robert1]

If I don't soon find the problem I will have to put a new ECM on it .If anyone has any suggestions please let me know.

Thanks,


Robert