is it a vacuum leak

cold start problem, brakes hard, low idle, after warm up everything is fine

 

Welcome to TacomaWorld Todd.
0 vehicle info = O replies

 

Yo Todd. If you elaborate we’re happy to help. But if you want answers people need information.

 

I'm not very mechanically inclined, but I think a vacuum leak would still show some symptoms after warmup. Correct me if I'm wrong.

 

Is there a check engine light?
Is there an error code?

 

No check engine light. Have not checked for an error code yet. Through testing I have discovered that there is no vacuum leak.

Symptoms are the first start of the day whether morning or afternoon is extremely hard to start. After the first start it will start all day long with no problems. Once started the brake pedal acts normally with no problems.

 

Additionally. First start has very low idle. After first start and engine warm up idle is normal on all subsequent starts.

 

Does the CEL light up with ignition on?

 

If the ignition is turn on but not started there is no CEL. After it starts still no CEL.

 

Check for a code with scanner. Sounds like your CEL might be burned out or unplugged. I’m pretty certain that if you have the key on but not started the light should come on. Are you the original owner?

 

CEL bulb is toast or disconnected
Run an OBD2 SCAN
Free at many auto parts stores

 

I am the original owner and had did not notice it was not on. Next step will be to check the code. Will update.

Thanks

 

In regards to the brakes, I’d treat that as a separate issue. For what it’s worth, the first press on the brakes on my truck has been a little jarring since i can remember. Could be an issue with something but hasn’t been an issue for me for 5+ years.

What year and engine is your truck? It does matter. For example my 2002 2.7 4cyl idles warm at 650rpm-750rpm. When it’s warming up the idle control valve opens more and it idles roughly around 1150-1250.

how old is your battery? Have you checked it’s health?
What is your idle at when cold with no accessories on (heater fan, a/c)? Does it change idle when you reach operational temperature?

 

Code P0118 - Engine Coolant Temperature Circuit High Input. Trouble Area: 1.Open or short in engine coolant temperature sensor circuit 2.Engine coolant temperature sensor 3.ECM.

Would this impact first start of the day?

Starting to suspect fuel pump or fuel filter??

 

Year is 2003 Tacoma Pre-Runner. Idles before this started was 8K rpm. Now until engines warms up it is 4.5K rpm with lots of misses and some back fires.

 

Replace the engine coolant temperature sensor and good luck!

 

I’d clean your mass airflow sensor first. If it’s dirty it could be underreporting air. It isn’t super likely but its super easy to do. Then i’d check to see if you have a sticky idle air control valve, or if the vacuum controlled throttle plunger is sticking.

 

Yes this would definitely have an effect on cold start idle. Hopefully the coolant sensor is easy to access. Make sure to check the wires at the connection too. If you have multimeter it would be good to check the sensor before replacing. Good luck and merry Christmas

 

I sincerely want to thank everyone who has given me good advice on this thread. This actually is the first thread I have ever received a response on.

I am at a standstill until next week thanks to external factors.

I noticed a pin hole at front end bottom of the air cleaner box. Also in the box there was a broken-up pecan shell, tons of leaves and it looks like something started chewing on the bottom of the air filter. The back of the air filter feeding the engine however was pristine. ?????

For those like myself who are not naturally mechanically inclined I have found two excellent videos that fit my engine.

To clean the Mass Air Sensor
https://www.youtube.com/results?search_query=cleaning+mass+air+flow+sensor+toyota+tacoma+3.4l

and to replace the Cool Temperature Sensor
https://www.youtube.com/watch?v=J9nHgZUoWyo

 

Hey Todd, how’s the project going?