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Randy, Auto Service Technician
Category: Honda
Satisfied Customers: 9710
Experience:  I have 25 Years as Automotive Technician
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Civic sport: Im having a problem with my Honda civic sport

Customer Question

Im having a problem with my Honda civic sport 1999. When I rev up (in neutral and when driving) it boggs down at 3000 to 2500. when you out gas It will only go up to 2000 and keeps doing this until it only goes up to 1500. Trying to figure out the problem I think its a faulty throttle position sensor but im not sure
Submitted: 2 years ago.
Category: Honda
Expert:  Randy replied 2 years ago.
Hi, my name is ***** ***** certified automotive professional with over 25 years experience. I will be glad to assist you with this.
yes, that sounds like it could the TPS however you will need to test the TPS with a volt meter. The voltage should be at 0.5 when throttle is not pressed then gradually increase to 4.5 volts at full throttle.Place your multimeter in Volts DC mode and with the RED multimeter lead probe the RED wire. This is the circuit that supplies the TP Signal to the PCM. The throttle position sensor has to remain connected to its connector for this test to work. Use the pointed probe of the volt meter to stick through the wire coating.
Ground the BLACK multimeter test lead on the battery negative terminal. Have you helper turn the Key On, but don't start the engine (this will power up the TP sensor).
Your multimeter should report .4 to .9 Volts DC. If your multimeter doesn't, don't worry about it just yet, continue with the other steps.
(STEP 4)Now, slowly open the throttle (by hand and from the engine compartment) while you observe the change in voltage numbers on your multimeter.
For this test result to be accurate, you need to open the throttle by hand and not from inside the vehicle.
As the throttle opens, the voltage numbers will increase. This increase in voltage should be smooth and without any gaps or skips. Once the throttle is wide open, your multimeter should read somewhere between 3.5 to 4.9 Volts DC.
Now, slowly close the throttle. As the throttle is closing, you should see the voltage decrease smoothly and without any gaps or skips, to the exact same voltage you noticed in step 4.
(STEP 7) now you'll need someone to help you lightly tap on the throttle position sensor with the handle of a screw-driver (or something similar, and I want to emphasize the words ‘lightly tap’) as you slowly open and close the throttle and observe the multimeter.
If the TPS is bad, the tapping will cause the voltage numbers to skip or go blank. If the TPS is OK, the tapping will have no effect on the voltage numbers.
Repeat step 7 several times to make sure of your multimeter test results.
Please let me know if this does not work for you or if you need any other assistance.
After we have your issue resolved please take a moment to rate my service positively.
Thank you very much!
Customer: replied 2 years ago.
We tested that yesterday, my friend is a mechanic and the tsp is faulty. I have one from the junk years coming in two days to put it in and test it. I just wanted to know if there was anything else that could cause this problem just Incase when I put this one in it continues to happen. The car is not drivable to a mechanic and just wanted to see if the fix was worth the car. Fingers crossed it's only the tsp by just trying to prepare for the worst
Expert:  Randy replied 2 years ago.
yes, that sounds like the issue. However let me know if it doesn't work and we can try some other troubleshooting. I am fairly certain that the TP sensor will solve the problem.
Customer: replied 2 years ago.
Ok perfect, when I get the new (used one) in on Thursday I'll message back if it doesn't solve the problem thanks for the help so far
Expert:  Randy replied 2 years ago.
Sounds good, your welcome!
Customer: replied 2 years ago.
I just got the new sensor in (used) and a whole new throttle body (used), also just for good measure I changed all the spark plugs with new ones.... It still continue to have the same problem. Please help
Customer: replied 2 years ago.
Expert:  Randy replied 2 years ago.
okay, have you checked the exhaust flow. It could be restricted and cause the low rpms.