• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

Idle's high when I come to a stop


88_ranger

Active Member
Joined
Sep 15, 2009
Messages
33
City
Hillsborough, NC
Vehicle Year
1988
Transmission
Manual
Hey there everybody...I have an 88 Ranger with the EFI 2.3L 4 cylinder and four spark plugs. The truck runs great but I am having this issue with the idle. When I'm driving down the road and I come to a stop light and I push the clutch in sometimes the RPM's will stay up at like 1700 and not come back down. But if I turn the truck off and restart it the RPM's will come back down to about 750 after a second.

I talked to someone about this and they thought it could be the EGR valve sticking. I replaced both the Idle air controller motor and the map sensor and this problem still persists. What do you guys think is going on? Thank you in advance for any help! :icon_confused:
 
weather

It is cold outside and it actually seems to have gotten worse since winter came. But it does it when it's hot out too. And yes it does get up to operating temperature and the heat blows hot from the vents.

Like I said if I cut the truck off and restart it the idle comes down fine.
 
It is cold outside and it actually seems to have gotten worse since winter came. But it does it when it's hot out too. And yes it does get up to operating temperature and the heat blows hot from the vents.

Like I said if I cut the truck off and restart it the idle comes down fine.

The idle air bypass valve sounds like she is sticking... or the butterfly is sticking.. Clean both with teflon safe TB cleaner... or You have a vaccume leak... I use starting fluid to find them myself but TB cleaner should work too...
 
Last edited:
mine has done the same thing multiple times, once i come to a complete stop it will settle back down to normal again. it has always been a vaccum leak, usually around the 'vaccum tee tree' that comes out of the intake on the drivers side. ive found that the vaccum caps offered by the chinese (nealy every available cap out there) only last a year or 2 before they start to crack.
 
vacuum leak

I'll check on that vacuum leak. But mine is acting the opposite of yours. It's fine when I'm driving but when I come to a stop that's when the rpm's go up. But I will check for vacuum leaks on the tree.
 
I know it's been a while but I just now found a possible fix to my high idle issue's that i've been dealing with for the past year. I decided to replace the TPS (Throttle Position Sensor). When I put it on and the started the truck back up, it actually got worse. Then I found out that it was adjustable from another post on this site. I made the adjustments and knock on wood the truck seems to be idling like it just rolled off the assembly line. I'll post an update in a couple days. Again thank you for your help everybody!
 
same thing

Mine was doing exactly the same thing...very intermittent! I replaced the idle air control valve, map sensor, egr valve control sensor, checked for vacuum leaks, and still could not figure it out. Then I replaced the TPS (Throttle Position Sensor) and it got worse. That's when it dawned on me that it the TPS is adjustable. With a Multimeter I belive the signal is supposed to read about .5 volts and when the throttle plate if fully open it's supposed to read about 5 volts. Well since I couldn't figure out how to use my multimeter I just kept adjusting it until the truck seemed to run good again. I've been running it for the past 2 days and knock on wood it hasn't returned after a full year of dealing with it! :yahoo:
 
Mine was doing exactly the same thing...very intermittent! I replaced the idle air control valve, map sensor, egr valve control sensor, checked for vacuum leaks, and still could not figure it out. Then I replaced the TPS (Throttle Position Sensor) and it got worse. That's when it dawned on me that it the TPS is adjustable. With a Multimeter I belive the signal is supposed to read about .5 volts and when the throttle plate if fully open it's supposed to read about 5 volts. Well since I couldn't figure out how to use my multimeter I just kept adjusting it until the truck seemed to run good again. I've been running it for the past 2 days and knock on wood it hasn't returned after a full year of dealing with it! :yahoo:

I'll keep my fingers crossed for ya, mate.
 
Vacuum leak unless you didn't clear the ecu after replacing the IAC.

Glad I saw this thread. Mines been doing the same thing but only when the a/c is on. Tps is only $24, might as well toss in a new one. Did you change the gasket too?

Yours is likely the IAC. Replace, clear ecu, then run it for at least a few days without the ac or defrost.
 
My 94 idles real rough when I stop . 4cy auto. It does it consistently, hot or cold. The steering wheel vibrates real bad . it's not that bad in park.
 
Rough Idle

My 94 idles real rough when I stop . 4cy auto. It does it consistently, hot or cold. The steering wheel vibrates real bad . it's not that bad in park.

Have you checked your timing lately? Just an idea...:icon_confused:
 

Sponsored Ad


Sponsored Ad

TRS Events

Member & Vendor Upgrades

For a small yearly donation, you can support this forum and receive a 'Supporting Member' banner, or become a 'Supporting Vendor' and promote your products here. Click the banner to find out how.

Recently Featured

Want to see your truck here? Share your photos and details in the forum.

Ranger Adventure Video

TRS Merchandise

Follow TRS On Instagram

TRS Sponsors


Sponsored Ad


Sponsored Ad


Amazon Deals

Sponsored Ad

Back
Top