Check Engine and Fluctuating RPM

[robgowild]

Guys please help kung ano kaya ang problem sa car ko, its Mazda 3 2006. I change the engine oil, air filter and spark plugs last week. So for that day ang ganda ng takbo smooth at lakas ng hatak. Now after a day of use coming from a short trip I started the car again and nag start naman without any problem but the CEL came on. So I checked everything wala naman ako nakita problem. I decided to reset it by removing the negative battery terminal. After that nawala naman yung check engine. Then after parking the car for hours sa mall inistart ko ulit then the RPM fluctuates while idle then namatay yung engine. I started the car again and this time okay na with no check engine light (this happen twice). Now after that everytime I started the car for the first time (cold start) the RPM fluctuates and parang mamamatay so I step on the gas to raise the RPM. Pag itinatakbo ko yung car ngayon ang hina ng hatak nya unlike nung 1st day ma tune up.

Now the problem is the check engine light is on again but I did not experience the fluctuating idle na namamatay makina pag cold start. I checked the laser irridium spark plug installed is right. After holy week ko pa mapa check yung car kasi eh.

Any ideas po kung ano problem? TIA

[go-to-guy]

if the check engine light turns on it's better to have it checked with a scanner para masabi kung ano talaga problem. Yung Civic ko nag-check engine last week & I had it checked sa Servitek, ang mahal nga lang, P950. It showed that I have to replace the Throttle Position Sensor. Nangyayari naman sa Civic ko is it jerks at times.

just to add: the check engine light has to be on when having it checked with a scanner.

[jaypee10]

wag ka muna mag reset .mag tanggal ng battery kapag papa scan mo na para mabasa ung anong sensor ang nagloloko.

[raycon_24]

madalas sira nyan ect sensor or thermostat ........ check mo kung puno naman coolant mo or baka nahugot wire https://www.ifixit.com/Answers/View/...0126+%26+P0128

*go-to-guy madali lang DIY pano retriece CEL code ng hondaCheck Engine Light codes (CEL) Diagnostic Trouble Codes (DTC) Malfunction Indicator Light (MIL) and - Honda-Tech

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madalas sira nyan ect sensor or thermostat ........ check mo kung puno naman coolant mo or baka nahugot wire https://www.ifixit.com/Answers/View/...0126+%26+P0128

*go-to-guy madali lang DIY pano retriece CEL code ng hondaCheck Engine Light codes (CEL) Diagnostic Trouble Codes (DTC) Malfunction Indicator Light (MIL) and - Honda-Tech

[jick.cejoco]

Looks like you need to go-to-somebody who knows

Check you IAC( idle air control) or clean it and reset. Also do a TPS sweep if you have access to a digital storage oscilloscope

[rodetor]

Did you replace your engine oil filter, when you had your oil changed? Or not?

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[rodetor]

You mentioned only, you had change your AIR FILTER.

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[rodetor]

Did you replace your OIL FILTER, when you made an Oil Changed?

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[ricciboy]

sir let the casa check your speed sensor

[jick.cejoco]

sir let the casa check your speed sensor

Speed sensors are input to the PCM as one of the enable criteria for O/D, power door lock, transmission/transaxle upshift/downshift, evaporative emission canister purge and antilock brakes. I do not understand nor have not experienced the speed sensor input for engine speed control

[robgowild]

Did you replace your OIL FILTER, when you made an Oil Changed?

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Yes sir. I also replaced the oil filter

[jick.cejoco]

Relevance people. Relevance.

[rodetor]

Check Engine Light (CEL) will only lit when a problem arise. Sa fluctuating RPM naman, ano ba pwede magdulot ng ganyan?

Opinyon ko lang ha. Ayon at base sa sinabi mo naging problema. Your car is Mazda 3. It runs in gas, and EFI. Kung wala problema sa Fuel Filter at Fuel Pump. Try mo ipalinis Throttle Body at Idle Air Contol Valve (IACV) nya. Baka stuck up lang IACV sa dumi.

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[rodetor]

Yes sir. I also replaced the oil filter

I asked because, when you change oil ang did not replace the oil filter. Oil will not recirculate well, and oil pressure would be insufficient, kahit ok sa indicator nya. Some of my friends experience troubles when they DIY changing oil without replacing it oil filters. The results are, poor performance, tourqe and speed.

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[JohnM]

Try checking the plug sa MAF sensor. Baka lumuwag when you replaced your air filter.

[robgowild]

Napa ayos ko na yung fluctuating RPM. Bale maluwag daw yung kabit nung mga spark plugs kaya ganun. I also have the throttle body cleaned and pina adjust ko yung throttle cable kasi may play yung accelerator. Ngayon okay na yung takbo pero bumilis siya, i don't know kung nanibago lang ako sa takbo or sumobra yung adjust ng throttle.

Napansin ko when in drive the idle is around 800 to 1k RPM then pag naka park mejo tumataas ng konti sa 1k RPM. Then also when I cruise in the neighborhood I no longer need to press the accelerator kasi umaandar na hanggang bumilis kaya alalay na ako sa break. Also kapag slightly sloping down yung road bumibilis agad yung takbo kahit di ako naka tapak sa accelerator then the RPM goes upro 1500 RPM to 1800 RPM. Normal lang ba yun mga sir?

[rodetor]

Directly proportional naman po ang RPM sa speed, when you shift in the correct proper gear position. Your acceleration of speed upon descending a slope without pressing your gas pedal indicates that there no slack or play on your throttle cable. Adjust nyo nalang po sa within specs.

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[sirkosero]

mukhang nasobrahan yung adjust sa accelerator cable.

that explains your 'parang bumilis' ,mataas na idling at yung rpm na tumataas while on a slope.

paadjust mo muna uli ng konti and check for stuck or maganit na linkages