Low idle

Welcome to 2CarPros.

A low idle can be a few things. First, I noted that you mentioned the idle air control valve (IAC). Since that is the component that is responsible for maintaining idle speed, that is my first suspect.

With that, let's confirm that it is working. Here is a simple test.

INSPECTION
1. TURN AIR CONDITIONING SWITCH OFF

See Picture 1

2. CHECK IDLE-UP
a. Start engine and run it at idle.
b. Fully turn the steering wheel.
c. Check that the engine speeds decreases when the vacuum hose of the air control valve is pinched.
d. Check that the engine speeds increases when the hose is released.

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If there is no change, remove the IAC and inspect where it mounts for dirt or carbon. Also, here are directions for testing the IAC / power supply:

ON-VEHICLE INSPECTION
IDLE AIR CONTROL (IAC) VALVE

1. INSPECT IAC VALVE OPERATION
a. Initial conditions:
- Engine at normal operating temperature
- Idle speed checked correctly
- Transmission in neutral position
- A/C switch OFF

Pic 2

b. Using SST, connect terminals TC and CG of the DLC3.
SST 09843-18040

c. After engine speed is kept at approx. 1,000 rpm for 5 seconds, check that it returns to the idle speed.

If the engine speed operation is not as specified, check the IAC valve, wiring and ECM.

d. Remove the SST from the DLC3.
SST 09843-18040

2. INSPECT IAC VALVE RESISTANCE

NOTE: "Cold" and "Hot" in the following sentences express the temperature of the coils themselves. "Cold" is from -10 °C (14 °F) to 50 °C (122 °F) and "Hot" is from 50 °C (122 °F) to 100 °C (212°F).

a. Disconnect the IAC valve connector.

Pic 3

Pic 4

b. Using an ohmmeter, measure the resistance between terminal +B and other terminals (RSC, RSO).

If the resistance is not as specified, replace the IAC valve.

c. Reconnect the IAC valve connector.

3. INSPECT AIR ASSIST SYSTEM
a. Initial conditions:
- Engine at normal operating temperature
- Idle speed checked correctly
- Transmission in neutral position
- A/C switch OFF

Pic 5

b. Using SST, connect terminals TC and CG of the DLC1.
SST 09843-18040

c. After the engine speed is kept at 900 - 1,300 rpm for 10 seconds, check that it returns to the idle speed.
d. Stop the engine.

Pic 6

e. Disconnect the air assist hose from the IAC valve, and plug it.
f. Start the engine and check that the idle speed reaches 500 rpm or below (the engine may stall).

If the idle does not reach 500 rpm or below, check for a leak between the air assist hoses, pipe and injectors.

g. Remove the SST from the DLC3.
SST 09843-18040

h. Reconnect the air assist hose to the IAC valve.

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If there are no problems with the IAC, then check to see if there are engine vacuum leaks. Here is a link that shows how that is done.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know if any of this helps or if you have other questions.

Take care,
Joe

As far as oil leak towing a trailer that far with an oil leak and your oil is down isn't to bad but you shold find the leak and fix it. Otherwise scan for codes and check fuel pressure with a gauge for the other problem. Auto parts rent it and can scan for codes.

Try cleaning the throttle plate on both sides and iac hole with choke cleaner clean shaft area on sides well. They get gummy and do that

Check out this video on how to clean the throttle plate! https://www.youtube.com/watch?v=JZoEb_hyWC8

This is normal and it happens to most cars depending on the quality of air the car is run in.

Glad we can help, please consider a small donation to help us keep the site going, the link is below.

Best, Ken

If check engine light is on scan for codes otherwise check for vacuum and air leaks. Air leaks like holes in duct work, grommets bad and leaking etc. Vacuum hoses cracked or broken