Fast Doc
Member
- Joined
- Feb 22, 2009
- Messages
- 142
- Reaction score
- 2
- Points
- 18
- Vehicle Year
- 1992
- Make / Model
- Ford
- Transmission
- Automatic
Good morning friends. I’ve been a member this forum for a very long time but have not posted in a while. I need some help with my beautiful 1992 4.0 V6 four-wheel-drive automatic transmission Ranger. It has 112,000 miles, and does not get used very much. I have other vehicles that I use most of the time, the truck mostly gets used for those times when I need a truck. Bad weather, pulling motorcycles, things like that. Maybe 2000 miles a year.
I’ve dealt with this problem intermittently for years, but it is becoming increasingly frustrating.
Sometimes, it will idle too fast, and there is nothing that I could do to bring it back down. It’ll usually start normally, idle a little bit faster than I think necessary (about 1000 RPMs when cold) then drop down to maybe 750 rpm’s, in gear. As the truck heats up, it’ll usually drop down to 650 rpm’s in gear, which I consider maybe a little fast but reasonable.
Occasionally however as it warms up, it idles faster and faster, sometimes much faster, which makes it a little bit uncomfortable to drive in stop and go traffic.
I have done a lot to try to sort this out.
Originally I thought it was a vacuum leak, but all the usual tests (spraying carb cleaner, starter fluid, around intake manifold and vacuum lines etc.) did not reveal any change in idle speed.
I checked the throttle linkage is which are clean and lubricated and definitely not hanging up.
I fastidiously cleans the throttlebody and the mass airflow sensor with the proper cleaners which didn’t have any effect.
New spark plugs, coil packs, fuel pump, air filter, fuel filter, etc. did not help. It can still idle as fast as 1500+ RPMs if in park or neutral.
I have not had the injectors formally cleaned, but I typically run Seafoam, which does not seem to help.
When I brought it to my mechanic, naturally it worked normally, so no diagnosis. It has never thrown a check engine light, and typically runs perfectly well except for this. You can also go days or weeks or a month at a time, and behave normally.
When it is hot, if I unplug the idle air controller (also new and replaced) it idles at about 500 in gear, which I consider to be perfect, however then it will not idle when cold.
Sorry for the long post, but this is been frustrating me, and I thought people would have an easier time figuring out what’s going on if I laid out the details. Thank you in advance for your help gentlemen.
Bill
I’ve dealt with this problem intermittently for years, but it is becoming increasingly frustrating.
Sometimes, it will idle too fast, and there is nothing that I could do to bring it back down. It’ll usually start normally, idle a little bit faster than I think necessary (about 1000 RPMs when cold) then drop down to maybe 750 rpm’s, in gear. As the truck heats up, it’ll usually drop down to 650 rpm’s in gear, which I consider maybe a little fast but reasonable.
Occasionally however as it warms up, it idles faster and faster, sometimes much faster, which makes it a little bit uncomfortable to drive in stop and go traffic.
I have done a lot to try to sort this out.
Originally I thought it was a vacuum leak, but all the usual tests (spraying carb cleaner, starter fluid, around intake manifold and vacuum lines etc.) did not reveal any change in idle speed.
I checked the throttle linkage is which are clean and lubricated and definitely not hanging up.
I fastidiously cleans the throttlebody and the mass airflow sensor with the proper cleaners which didn’t have any effect.
New spark plugs, coil packs, fuel pump, air filter, fuel filter, etc. did not help. It can still idle as fast as 1500+ RPMs if in park or neutral.
I have not had the injectors formally cleaned, but I typically run Seafoam, which does not seem to help.
When I brought it to my mechanic, naturally it worked normally, so no diagnosis. It has never thrown a check engine light, and typically runs perfectly well except for this. You can also go days or weeks or a month at a time, and behave normally.
When it is hot, if I unplug the idle air controller (also new and replaced) it idles at about 500 in gear, which I consider to be perfect, however then it will not idle when cold.
Sorry for the long post, but this is been frustrating me, and I thought people would have an easier time figuring out what’s going on if I laid out the details. Thank you in advance for your help gentlemen.
Bill