Idle issues

I have a 1999 Toyota Tacoma TRD SR5 4x4 manual 5 speed with the 2.7L engine. I bought it with a high idle i have gone through it many times as well as mechanics and I can't find a vacuum leek any where. It stays at 1500 rpms when it's cold and warm. The TB has been cleaned as well as the TPS and IAC. Any one have ideas or suggestions

 

Welcome to the forums!

Have you tried disconnecting the IAC valve to see if the high idle will drop? Got any photos of your engine bay?

Have you hooked up an OBDII scanner to read what the sensors are reporting? Is the check engine light on?

Is the engine stock or has anything been added or deleted?

What did you do to check for a vacuum leak? Did you use the propane method?

 

No I have not tried unplugging it to see if there is a change. It's a brand new engine I bought it from Toyota with 0 miles nothing is added or removed from the stock ways. No check engine

 

Post up some photos of the engine bay. Make sure the photos are in focus, please.

 

I don't know how to post a picture

 

So I unplugged the IAC valve and it idles normal the idle sits around 750 like it is supposed to but when you plug it in it spikes back up to 1500 does this mean I need a new IAC

 

What color are the wires on the IAC valve connector? Did they replace or splice the wire harness to make this new engine work? Did they install a new ECU from a different year or type? Exactly what was replaced when they installed the new engine?

 

Could you pull the IAC valve off and snap some pictures of it? I'm curious on the actual part number that should be stamped on the side of it. I'm also curious if someone tampered with the IAC valve settings as well.

 

It's an OEM IAC valve the one in there was stock then I bought one from Toyota and it still doesn't idle at 750 when I drive the truck with out it plugged in it backfires and wants to stall out

 

I would stick a OBDII scanner on there and see what's being reported back to the ECU. Wouldn't hurt to see...

 

Lol I got really confused when I saw my truck as your avatar....I had a ifle over 2k...two throttle bodies later and it's at 1300....I give up

 

Would not having a thermostat valve have something to do with it? The stock one wouldn't open so the engine would get to hot for my comfort so I took it out and haven't had a problem with over heating but is that why I might have a

 

Try putting it back in and see if the high idle goes away...

 

That could be your problem... Your engine runs in open loop "high idle" mode until it is warmed up. If you have no t-stat, it may not be reaching the temp required by the computer to go into closed loop. you should definitely buy a new properly functioning t-stat and put it in.

 

I bought a new thermostat and put it in. It solves the high idle. But it goes back to the problem of overheating. The top hose for the radiator is hot and the lower hose is cooler than the top meaning the water isn't circulating. I checked the thermostat to make sure it opens correctly and at the right heat, and it did so why is it still not circulating

 

When you installed the new thermostat, which direction was the jiggle valve? I believe it's supposed to be at the 12 o'clock position.

Are you using an OBDII reader to get your temp readings? If so, what temps is the ECU seeing? ...or are you going strictly by the instrument gauge reading? Post up pictures of the gauge when you think it is overheating.

The lower hose is supposed to be cooler than the top hose. How are you checking the flow of the coolant? Try this when the engine is cool. Remove the radiator cap and start the engine. When the coolant gets to operating temp, check the radiator for coolant flow. You should be able to see it through the radiator fill neck.

 

I fixed it the thermostat was getting stuck open witch was causing the high idle. Once I put the new thermostat in the truck was overheating so I checked the radiator to see if the coolent was flowing when the truck reached its temp but it wasn't. So I took the radiator out to check for and thing that would be clogging it as it had some backed up gunk. Runs great and idles and the temp stays right between the hot and cold.

Thank you Guys for all the help and ideas for what could be causing the issue.

 

Do you guys have any ideas or tricks on how to gain just a little more power? I have 33/15/12.50 maxxis bighorn tires. I can hardly us my fifth gear cause of the bigger tires.

Im open to any ideas or suggestions. Trying to keep it to pass smog

 

You shot yourself in the foot by putting on those larger tires. You have 3 real choices to restore your acceleration:

1 - go back to stock-size tires
2 - supercharge it
3 - re-gear the differentials to 4.88

#3 is the best option, IMHO. May cost up to a grand, though.