Hesitation And Farting Sound On 2000 Corolla - Toyota Corolla, Chevy Prizm (1998-2008)

Hello first time poster w

I've had hesitation and the fuel bank too lean/random misfire codes for a few years with my corolla.. I've replaced the plugs once,replaced PVC valve, I've tried cleaning my MAF sensor multiple times which seems to provide moderate and short term improvement, but that might simply be me imagining things. I've also replaced spark plugs and ran some fuel system cleaner through a few times

There seems to be a rumble/farting noise upon initial acceleration. Read somewhere that it might be the tensioner pulley.

I went ahead and ordered a new MAF sensor and O2 sensor as it has 130k miles, but i'm considering taking off the intake and cleaning it out as when I change out the coolant and change the belt. I'm suspecting the belt tensioner pulley might be a culprit for the noise.

Haven't checked compression; vacuum seems to be alright, although theres a little crack on the hose from the PVC valve

Any ideas or guidance? Is there an EGR valve on this model? fuel injectors bad? Transmission issue?

THANKS

No EGR on this generation of Corolla, all handled by the valve overlap strategy. Have you tried loading the engine from a standstill and seeing if you can reproduce the rumbling/farting noise? If it is a bad tensioner, it will do this if the car is revved in gear with the brakes full on or at a speed. If it doesn't, could be suspension or transaxle/powertrain related. Could be anything from a worn axle, to worn bushings, to worn engine/transaxle mounts, to loose or worn suspension, to even possible internal transaxle issues.

Need a bit more information - was this noise present when you first had the lean run/misfire conditions? Did this noise just suddenly just start or did the noise gradually get louder over time? What did the plugs look like when you pulled them out, where they pretty similar in appearance, any signs of detonation, overheating, carbon or oil contamination? How is the overall fuel economy of the car, did it start pretty much the same or did you notice a sharp increase or decrease at any point? Have any oil consumption on this car?

to be honest, the noise has existed for years now; it's more pronounced initial under load, but it is reproducible at a standstill.. seems to dissipate at higher RPMs

haven't pulled the sparks in a while.. did get a misfire on piston 2; i switched the coils and so far only get random misfire. I fried my multimeter so i'm not able to test their resistance

as for fuel economy I am not sure.. probably a little below where it should be, but it's constantly weighted down with stuff in it (it's my mom's car and she keeps too many damn things in it !)

Hmm. Could be a bad tensioner, but if it held up for this long, might be one of the pulleys giving you trouble. A faulty tensioner will destroy itself pretty quickly, haven't seen one start off bad and stay the same over a couple of years, assuming the car is driven fairly regularly.

Be worth a shot pulling the plugs and giving them a quick look. A loose plug, or one that is heavily oil fouled will cause a misfire and can manifest as a low grumbling/rattling/rumbling sound.

I remember changing the plugs before, and the issue continued.. can i use copper plugs in the engine, despite it specifying irridiums?

Copper plugs will work, just make sure the plug reach is not too deep, or they will touch the top of the pistons - also means you'll have to change them out sooner, every 10K miles or sooner is not out of the question. This engine is known to be tough on plugs.

Also might be worthwhile to check on the pump, filter assembly (in the tank), and pressure regulator. Checking fuel pressure will be next on my list - unfortunately, there is not valve on the fuel rail - you have to plumb in a t-fitting to hook to a pressure gauge. Compression check would also be at the very top og my list - no sense pumping a lot of time and effort into the engine if the compression is low. Specs have compression at 145-218PSI with no more than 15PSI variance in any cylinder, done on a warm engine. Also do one cold (dry) and cold (wet) to baseline/bracket the compression for the engine as well.

thanks will do

Performance has declined considerably.. i'm waiting on my compression tester to arrive from amazon.. on ODB II I've got a cylinder 3 misfire code, after switching cyls 2&3's coil stack (before it said cylinder 2 misfire), so maybe i'm lucky and that what it is. I haven't checked the plugs though because it's hard to get to the car with the engine cooled off in this summer heat and constant errand running

I decided to buy a couple of used shouldbeDenso coils off Feebay for 45$.. fingers are crossed!

finally got compression tester.. it blew past the 210psi mark on all 4 cylinders.. I noticed there was a slow decay from the top marks until i discharged at around 180psi over a 20 second or so timeframe. Perhaps I didn't tighten the hose fitting down enough (did it by hand), or is that normal?

changed out the two middle ignition coils, and the oxy sensor along with plugs.. performance improved moderately, but there is still hesitation and poor running for about 20 secs after starting from a warm or cold (even worse) engine.

noticed theres oil in cyls two and three, so I suppose the valve cover gasket is bad.. but cleaning everything doesn't really make a positive difference performance-wise

I should've asked before - How do i check the coils? pull em out, slip a spark plug in and crank the car?

haven't done any vacuum testing.. spraying carb cleaner over the hoses and manifold a sufficient test?

I'm reluctant to do the fuel testing to be honest!

Should only need to be hand tight - sometimes coating the threads with some oil or grease can help. But from your description, sounds like the compression test was fine.

Oil that is pooled down in the sparkplug wells will cause a misfire. Pretty simple matter to change out the valvecover gasket - will also give you access to the cams and valvetrain to see how everything is looking.

Checking coils - that is exactly how you check them. They make an a SST adapter cable to lengthen the wiring to the coil for easier testing, could be hard to find though. Simplified steps - do this only over a couple of cranks - otherwise you could load each cylinder with a lot of fuel - watch for accumulated gasoline vapor - you could disable fuse to fuel pump to prevent it from pumping any gas to start out with, though some gas will still be in the fuel rail. Stick plug into coil pack, ground plug to chassis ground, crank engine and observe spark.

Check for vacuum leaks - you could use carb cleaner or similar solvent, just have to watch what you spray and note that it will soften the rubber/plastic bits (ie, eat the part you just sprayed). Soapy water in the spray bottle can work just as well, in that manner. Just hit the hoses around the manifold, hose unions, vacuum hoses and check valves on the brake booster assembly, around throttle body, around intake manifold - that should be sufficient. There are other vacuum areas - EVAP for example, but those would not affect the idling and performance in the manner you are mentioning.

When you changed the O2 sensor - which one did you end up with? Denso OEM or aftermarket? Some 1ZZ-FE engines are quite picky, some don't seem to like anything other than Denso OEM - possible impedance mismatch issue. Same with the coils - did you get OEMs one or aftermarket? Probably not a bad idea and check all chassis grounds and wiring to the coils/injectors. Another area this engine is sensitive to is electrical noise. Too much noise can lead to unexpected behavior that can be really tough to diagnose.

Given that you replaced the plugs, O2 sensor (assuming upstream one), two middle coil packs, and verified compression and assuming the injectors, fuel delivery, and the induction system are fine - tt almost sounds like the engine is missing due to a ignition timing issue. Unfortunately, you cannot "slew" the timing on a modern car anymore, without the Toyota handheld scanner. All that is set by the ECM. You can still double check the timing on the car though - see if it advances it as RPMs climbs. VVTi system malfunction could also be a possibility - though diagnosing that is a little more involving. Quick check is the disconnect the OCV valve and see if the idle changes or not. If it doesn't change - then the VVTi/OCV system is suspect.

Thanks fish for the follow-up response.. I will need to read through it a few dozen times to fully understand it all haha.

I did change out the upstream O2 sensor with a Denso from rockauto. The sensor replaced had white charring, presumably due to a lean bank?

Also changed the timing chain tensioner recently

I will try pulling the PCV valve hose and cleaning out the OCV filter when i get the chance. Not exactly sure how to probe with a multimeter to determine the grounding issues

Also tried blocking the rear exhaust for a couple seconds, but saw or smelled nothing that indicated a leak upstream

I hosed the TB down with soapy water to no avail.. didn't get a chance to take the engine cover off yet to get the PCV and breather tube or whatever it's called just yet, but I'm expecting similar results. I changed out the pcv with some autozone piece not too long ago incidentally

ODB-II reader flashed P0303 again along with the random misfire code + bank 1 too lean, which is for one of the ignition modules that I replaced, so I'm suspecting that the injector is the culprit, although the oil seepage problem continues in 2&3 spark holes. I'm torn as to whether i should get a fuel gauge(50ish$) or to buy four reman injectors and take a gamble. I will say that i'm in NC so we have lots of pollen and gunk that probably made its way into the gas line, and we almost always run between a quarter tank down to E on the fuel gage all the time so I dunno, possible particulate contamination?

Car continues to have a kind of wobbly farty noise when a gear load is applied. Otherwise there's a pretty gnarly metal rubbing sound coming from either the chain area or one of the accessories. TIming tensioner was changed in an attempt to remedy noise; the water pump has never been changed; at least not since 12k miles when we bought it (now at 133k). Also noticing a pronounced HUM noise.. I thought it might be the transmission oil pump, so i checked the trans filter and it was empty; the magnets had some fine black grit, and that was all. Seems to shift alright, apart from this hesitation.Perhaps the mounts are bad, flex plate bolt hole cracked, hum from crank harmonics due to misfires?

The sensor replaced had white charring, presumably due to a lean bank?

White residue could be from oil consumption or fuel additives - mine looked about the same way, when I replaced the upstream sensor on my 2003 Matrix.

Not exactly sure how to probe with a multimeter to determine the grounding issues

Easiest way is to measure between the negative battery terminal and various chassis grounds (just follow the wires running to the chassis) with a multimeter set to millivolts. If the multimeter has a reasonably high impedance (most do), then you should be able to see if there is any voltage difference between the two points. Ideally, should be nothing there (0 millivolts) - but possible, due to the resolution/sensitivity of the multimeter, you could see 10s of millivolts from background noise. If you measure 100s of millivolts, that could indicate a possible ground issue at that point.

ODB-II reader flashed P0303 again along with the random misfire code + bank 1 too lean, which is for one of the ignition modules that I replaced, so I'm suspecting that the injector is the culprit, although the oil seepage problem continues in 2&3 spark holes. I'm torn as to whether i should get a fuel gauge(50ish$) or to buy four reman injectors and take a gamble. I will say that i'm in NC so we have lots of pollen and gunk that probably made its way into the gas line, and we almost always run between a quarter tank down to E on the fuel gage all the time so I dunno, possible particulate contamination?

I'd address the oil leak soon, likely it is those o-rings that sit between the valvecover and the sparkplug tubes. Injectors can be cleaned, depending on where you send them, they can turn them around in 24-48 hours. Cost is variable as well - simple cleaning might run $10-$20 each, if you want them balanced, could run in the $50+ range each. A fuel pressure gauge is a good tool to diagnosis a fuel issue in the rail or from the pump. Though not easy to measure the fuel pressure in the returnless fuel system that this car uses. You have to install a SST (Special Service Tool) fuel-T to allow you to measure the pressure to start with. Might be able to rent those items, so I'd call around and check.

Car continues to have a kind of wobbly farty noise when a gear load is applied. Otherwise there's a pretty gnarly metal rubbing sound coming from either the chain area or one of the accessories. TIming tensioner was changed in an attempt to remedy noise; the water pump has never been changed; at least not since 12k miles when we bought it (now at 133k). Also noticing a pronounced HUM noise.. I thought it might be the transmission oil pump, so i checked the trans filter and it was empty; the magnets had some fine black grit, and that was all. Seems to shift alright, apart from this hesitation.Perhaps the mounts are bad, flex plate bolt hole cracked, hum from crank harmonics due to misfires?

You can try running the car without the serpentine belt, to see if you can isolate the sound. I won't hurt the engine to run in for a very short time without the belt, just make sure the battery is charged up well - as the alternator will be taken out of the picture in that case. You can also spin the pulleys by hand to see if any have slop or are binding on you. Some of the symptoms you have could be attributed to an exhaust leak. This generation of Corolla is quite likely to leak right by the two front exhaust gaskets. One is held by spring-bolts between the exhaust manifold and the front pipe, and the other is under a band-clamp between the front pipe and the catalytic converter. If they are leaking, car will be low on power, running poorly under load, and may cause all sorts of CELs to pop up.