250K miles, original gas motor. Codes P0300, P0301, P0302. If anybody has some suggestions for the cause of the trouble, please write. Things tried: -Replace spark plugs. Observation- spark plug wells clean and dry. Plug 1 had way more gap due to erosion than 2, 3, 4. -Replace coil packs. -Replace PCV valve Observation- old valve still worked fine -Remove intake manifold assembly; clean and reinstall. Observation- manifold interior dirty with carbon; this was easily cleaned out. Air flow valve unit had some grime, easily cleaned out. Valve turns easily, spring easily returns valve to home position. -Unplug coil pack electrical connectors, clean contacts -Unplug fuel injector connectors, clean contacts. After doing all the things listed above, here is some info from the code reader. Freeze Frame Data: P0301 FUEL SYS 1...CL FUEL SYS2...NA CALC LOAD (%) 16.9 ECT(DEG F) ...136.4 STFT B1(%)...5.5 LTFT B1(%)...0.0 ENG RPM...1698 VEH SPEED (MPH)...2 SPARK ADV(DEG)...14.5 IAT(DEG F)...78.8 MAF(LB/MIN)...0.6 TPS(%)...15.7 O2S B1 S2 (V)...0.640 STFT B1 S2(%)...99.2 RUN TIME (SEC) 43 LAMBDA B1 S1...1.023 O2S B1 S1(V)...3.425 COMMAND EVAP...0.0 WARM-UP DTC CLR...0 CLR DIST (MILES) 1 EVAP_VP(INH20)...0.272 BARO(INHG)...29.8 CAT TE 11(DEG F) ...534.0 CAT TE 12(DEG F)...228.4 ECU VOLTS (V)...14.003 LOAD VALUE (%)...16.5 EQ RATIO...1.004 REL TPS(%)...0.0 AMBIENT(DEG F)...60.8 TPS B(%)...51.0 COMMAND TAC (%)...15.7 CLR TIME...0H11M Thanks anybody who may have suggestions. I have basic car repair tools, code reader, multimeter, Haynes book. -FM
Did you clean the airflow sensor as well as the temperature sensor in the MAFS? The temperature sensor is easily seen externally down the side of the probe. The airflow sensor is internal and hidden a little. This post by Mr_Guy_Mann has a good picture showing the airflow sensor pickups. Generally speaking miss-fire codes (P03xx) are due to bad plugs, bad coils, or bad injectors. You replaced the plugs and coils. Did you use good quality (NGK or Denso Iridium plugs) and Denso coils? Good quality means not from Amazon or eBay, which if cheap are likely to be counterfeit parts. My only other (clutching at straws) thought is a leak in the plumbing after the MAFS that is letting in unmetered air.
I would drive the car while monitoring fuel trim numbers. Short term and long term fuel trim should stay close to 0% under most conditions. Does it ever go above +10% or below -10%, if so then when? MAF sensor problems, vacuum / induction leaks, or injector problems should all cause abnormal fuel trim numbers. Do you feel jerking sensations (stuttering, hesitation) from the powertrain when driving? Does the MIL (check engine light) flash? You need to be certain that your ignition system is up to snuff. IF that's provably ok, and fuel trim is reasonable, then you have to look at other possibilities, like head gasket issues, valve clearance out of spec (extremely rare on Toyotas), or a compression problem. Posted via the PriusChat mobile app.
EDITED TO CORRECT CODE. Vehicle was in storage for past 1.5 yrs. Getting it back on road: smog check next hurdle. Vehicle only throws one code: P0301, a few times per week. Seems to throw this code when engine is cold, within minutes of starting up. Pulled spark plugs (NGK iridium BKR5EIX-11, from Autozone) for visual inspection; photo attached. Plugs have <10k miles on them. Motor has 220k miles, original no rebuilds. 2, 3, 4 have uniform appearance: Center electrode: unworn, minimal residue. Center insulator: white, no residue. L- leg of electrode: light grey particles. Sharp and unworn metal. Plug steel body: black dry residue. Plug body machine screw threads: light film of liquid, smells like oil. 1 appearance: Ctr electrode sharp, unworn, covered with grey dry residue. Ctr insulator: covered with grey gry residue. No white ceramic visible. L-leg: light grey particles. Sharp and unworn metal. Plug steel body: black dry residue. Plug body machine screw threads: light film of liquid, smells like oil. Gas in tank is now 1.5 yrs old. Fuel injectors and pump are original OEM. I want to root csuse eliminate or at least suppress likelihood of P0301 to get past smog. Coolant doesn't look like/smell like it has oil contamination. No leakdown test on motor yet.
EDITED TO CORRECT CODE. Switched coil between 1, 2. Threw p0301. Switched plugs between 1, 4. Threw p0301.
There's something going on in cylinder #1. Siphon out the gas in the tank and refill with fresh gas and dump some CAT safe injection cleaner in at twice the recommended concentration. I'd like to say it's a fuel quality issue, but all your plugs should be the same - since they're all feeding off the same tank. Try running the car like that for a tank of gas and hope it clears itself up. Also move #1 plug to #4 position and see what happens. It won't hurt. Your trying to see if that clean #4 plug turns grey too - that'll tell you that there's an ongoing issue in cylinder #1. Good Luck..
Assuming you have a P0301 misfire code, does it misfire all the time when it warms up or only under load (or somewhen else)? Per post #3, what are fuel trim values (short term + long term = total trim) at hot idle, high idle, light accel, and 40mph cruise? That plug for #1 has deposits that look like excessive oil burning (likely stuck rings). But that alone shouldn't cause immediate misfire. Continuous misfire on a single cylinder could be a restricted or stuck fuel injector, mechanical compression fault, or electrical problem for the injector or coil (should set other codes but doesn't always do that) You already swapped coil and plug around, so that eliminates the "easy" stuff. Might be time for a compression test. Head gasket leakage usually first causes brief misfire on cold start (the coolant fouls the spark plug). There is coolant "loss", eventually engine overheat and "steam cleaning" the plug & combustion chamber. Posted via the PriusChat mobile app.
As you were: Code is p0301. Cleaned MAF. Replaced air filter. Threw p0301. Next look at switching injectors, see if issue migrates with suspect injector. Also look at compression/leakdown for findings. Thanks all for suggestions.
