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.

A: Hi there. Check the Manifold Absolute Pres...

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!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: My check engine light came on AND my cruise control light started flashing, same exact time.

Hello. Subaru has designed their vehicles to turn on the cruise control light when their is a problem with the power train system. This keeps you from using the cruise control when there is a problem. If there is a...

Q: Truck stalls when shifting into drive from park or reverse

Hi there. The vehicle running great, once past the initial stall, leads me away from a fuel delivery concern. The stalling issue may be, the minimum airflow rate is not properly set. This could be the result of a dirty...

Q: Why does my 2006 dodge charger keep stalling?

You may have a dirty or failing idle air control valve. The idle air control valve reads the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. Since...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...