Skip the auto shop - Our mechanics make house calls

Q: Engine light and throttle body light come on every morning when first start

asked by on

I installed a crate engine and drove for about 700 miles with no issues and then I had the a/c recharged from having replace the engine. The next day I started it in the morning to go to work and the check engine and throttle body lights came on, I have a handheld scanner and it said MAP sensor P0108. So I replace the map sensor and the next day same thing when I started it. Same code P0108 map sensor, so then I took it to a local shop and had them hook it to there computer and they got same thing. So I replaced the map sensor again and same thing happen the next morning, so I took it back and the scan it and said I need to replace the throttle body. So I did and reset it to what the manual said and the next morning yep same thing, so then I took it to the dealer to have them check it and they had know idea. So 170.00 dollars later I took it back home, I check all wiring and connector's could not find nothing wrong except the air charge temp sensor was broken so I replaced it.

My car has 202700 miles.
My car has an automatic transmission.

Hi there. Check the Manifold Absolute Pressure (MAP) sensor voltage. Key on engine off it should be approximately 4.5 volts, idling in the 1 volt range and go over 4 volts at a snap throttle. Then, check the Throttle Position Sensor (TPS) voltage in the pedal follower test with the scan tool. At closed throttle TPS #1 should be approximately 0.5 volt and at Wide Open Throttle (WOT) over 4 volts. TPS #2 should read 4.5 volts closed and 0.5 volt at WOT. If everything is working correctly, then you will need to have your engine control module (ECM) flashed (reprogrammed) to match the crate motor. If you need further assistance troubleshooting your vehicle, then seek out a technician, such as one from Your Mechanic, that can assist you with your vehicle.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  • Home
  • Questions
  • Engine light and throttle body light come on every morning when first start

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: My car is hard to start when it's cold. When it's warm it will usually start just fine and I'm not sure what to do

There can be several codes pertaining to the camshaft sensor and you did not supply the code you are getting. You may be having a problem with the camshaft timing phaser not being in the correct position when engine is...

Q: Timing chain gears.

There are several parts that will need to be changed when doing a timing chain replacement. Typically, you will need to replace the chain, the timing gears, and any guides or tensioners that are associated with the timing chain. Also,...

Q: None of my electrical components are working

Hi, thanks for writing in. If nothing operates, the circuit is not complete. What you want to do is select one of the non-working circuits and simply trace the circuit until you find the open. Inasmuch as nothing works, you...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...