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Yes the bulb works. Actually checked the codes using jumper wire in diagnostics connector and got the 21 = oxygen sensor. Probably the light would appear after running longer without the sensor. I still wonder is it normal that I can't feel any difference with and without oxygen sensor?
Your '99 is OBD2 compliant. I've read that jumpering the diag connector doesn't work, so I'm not sure if that code 21 is valid. It would be best to read the codes with an OBD2 reader. Simple ones are cheap these days; about $10-$20 for a basic one. Or most auto parts stores will read 'em for you for free.
 

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Your '99 is OBD2 compliant. I've read that jumpering the diag connector doesn't work, so I'm not sure if that code 21 is valid. It would be best to read the codes with an OBD2 reader. Simple ones are cheap these days; about $10-$20 for a basic one. Or most auto parts stores will read 'em for you for free.
I think the code valid, because the oxygen sensor was disconnected. I am so sad that here in Europe the cars have had to be OBD2 compliant from 2001 -->.

My car has Toyota DLC-1 under the hood, and DLC-2 close to the pedals inside. Similar to ones in picture here https://mechanics.stackexchange.com/questions/30227/what-kind-of-dlc-did-toyotas-have-before-switching-to-obdii However, the OBD2 connector is missing, it has even empty bracket for it though. That's a bummer when troubleshooting.

Edit: And I tried two different OBD2 readers with adapter before finding the truth
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Ah, sorry. I assumed you were in North America. Carry on.
 

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For a while now, the car has been doing this thing where it bucks/jerks when in low gears. It only does this when I step abruptly on the gas, or abruptly let it go. It is especially noticeable when the engine is cold. I haven't been having any real problems with the car. It idles fine, and the engine sounds fine, but this little problem is kind of irritating.

Like I said, when I'm traveling at higher speeds it's not a problem. Also, after the car's warmed up it's not as noticeable (but you can still tell it's there). Has anyone experienced a problem like this, or have any idea what it might be?
I've been giving this some thought and relating it to a problem I had once. I think this is fuel related not ignition. I think the engine bucks/jerks under acceleration because the mixture is running lean. A lean mixture is harder to ignite.

I believe this is more of a problem when cold because a cold engine requires a rich(er) mixture. It does not happen at speed because there is little demand for larger amounts of fuel when cruising. I would test this up a steep hill and see if the symptoms get worse - that's when the engine is under load and needs more fuel.

It is possible the fuel filter is clogged. Given this is a 99 is the fuel filter original? A pressure test may not reveal low pressure as it would only occur when flow is needed for acceleration so your idle pressure would show normal.
 

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I've been giving this some thought and relating it to a problem I had once. I think this is fuel related not ignition. I think the engine bucks/jerks under acceleration because the mixture is running lean. A lean mixture is harder to ignite.

I believe this is more of a problem when cold because a cold engine requires a rich(er) mixture. It does not happen at speed because there is little demand for larger amounts of fuel when cruising. I would test this up a steep hill and see if the symptoms get worse - that's when the engine is under load and needs more fuel.

It is possible the fuel filter is clogged. Given this is a 99 is the fuel filter original? A pressure test may not reveal low pressure as it would only occur when flow is needed for acceleration so your idle pressure would show normal.
I am not the thread starter but necro-bumped and re-used this thread since I have same problem (Yes, it is confusing)

I tried to find any vacuum leaks with throttle body spray but failed to do so. My idle has always been rather lowish than high so I guess I don't have vacuum leaks then.

I replaced the fuel filter (previous one was not original), did not have any effect. I don't have tools to check fuel pressure but the problem does not occur on very low or high RPMs so I guess it is not that either.

Did some more random trouble shooting. Disconnected ECT sensor got engine light but it has absolutely no effect on anything (tested with warm engine). Also disconnected MAP sensor and the car behaved very badly with it disconnected. Cleaned IAC valve, it did not look too bad and its resistance is fine.

O2 sensor seem to start have voltage values fluctuating quickly after starting the engine as cold. However it is hard to see actual values with multimeter. I am wondering that could it be that my car does not go to closed loop since I absolutely felt no difference with disconnected O2 or ECT sensors? Anyway couldn't old bad O2 sensor cause hesitation on stepping on gas or releasing it if its acting too slow? Also noted if I actually put the pedal to the medal very quickly the car never hesitates. If I understood right throttle very open ignores any sensor data anyway!(?) (And reminder that my car just has single upstream oxygen sensor)

E: Thing such as engine coolant temp would be so nicely seen from OBD2 data. Pity that I am missing that.
Did some resistance measurement, seemed to be close to what it should..
 

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O2 sensor seem to start have voltage values fluctuating quickly after starting the engine as cold. However it is hard to see actual values with multimeter. I am wondering that could it be that my car does not go to closed loop since I absolutely felt no difference with disconnected O2 or ECT sensors?
If you're using a multimeter as scan tool you will get frustrated very quickly. First a digital MM will not respond quickly enough to read much. You'd need an analog meter for that and then reading values would be difficult. What you really need is fuel trim numbers, but for that and O2 voltages the scanner would need to show a graph so you could capture it by eye. The numbers change very quickly.

The O2 voltage fluctuates between .1 and .9 volts - that's normal. It does this because for the CAT to operate efficiently it needs to run lean to rich fuel mixtures. The O2 sends rich/lean data to the ECU which changes the fuel trim from rich to lean and back again, this in turn makes the O2 show rich/lean voltage.

Anyway couldn't old bad O2 sensor cause hesitation on stepping on gas or releasing it if its acting too slow?
I doubt it.

Also noted if I actually put the pedal to the medal very quickly the car never hesitates. If I understood right throttle very open ignores any sensor data anyway!(?) (And reminder that my car just has single upstream oxygen sensor
When the engine is cold (open loop) the fuel trims are set by factory presets. Once the engine goes into closed loop then the O2 sensor is used to determine fuel trims. There is a short term and a long term. The long term is the learned fuel trim from data in the short term. If you had a scanner with graphing software you'd be able to see long term trims quite easily.

To adjust for full/fast throttle and slow throttle, or no throttle the Throttle Position Sensor (TPS) is used. It will tell the ECU that for rapid acceleration the fuel trims need to be rich and so override the O2 data. It is possible you have a bad TPS. It also adjusts shift points.
 

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If you're using a multimeter as scan tool you will get frustrated very quickly. First a digital MM will not respond quickly enough to read much. You'd need an analog meter for that and then reading values would be difficult. What you really need is fuel trim numbers, but for that and O2 voltages the scanner would need to show a graph so you could capture it by eye. The numbers change very quickly.

The O2 voltage fluctuates between .1 and .9 volts - that's normal. It does this because for the CAT to operate efficiently it needs to run lean to rich fuel mixtures. The O2 sends rich/lean data to the ECU which changes the fuel trim from rich to lean and back again, this in turn makes the O2 show rich/lean voltage.



I doubt it.



When the engine is cold (open loop) the fuel trims are set by factory presets. Once the engine goes into closed loop then the O2 sensor is used to determine fuel trims. There is a short term and a long term. The long term is the learned fuel trim from data in the short term. If you had a scanner with graphing software you'd be able to see long term trims quite easily.

To adjust for full/fast throttle and slow throttle, or no throttle the Throttle Position Sensor (TPS) is used. It will tell the ECU that for rapid acceleration the fuel trims need to be rich and so override the O2 data. It is possible you have a bad TPS. It also adjusts shift points.
Thanks for the comments!

Yes I noticed clearly that digital multimeter is too slow to actually see how O2 sensor's output voltage actually fluctuates. Probably it does not sound typical problem caused by O2 sensor, but the came across this thread https://www.toyotanation.com/forum/103-camry-3rd-4th-gen-1992-1996-1997-2001-1st-gen-solara-1999-2003/409501-99-camry-misfiring-sputtering-hesitating-etc-tried-everything.html I think it is worth of trying since it is not too big investment.

Actually the TPS was first think I was thinking of at the beginning. Then I tried to unplug it and the car actually felt bit better and got another sensor from a junk car. My hopes were high but it made no difference. With TPS unplugged the idle was very high sometimes which probably smoothened the gear shifting bit (I mean not drop exactly to that 2000rpm+ area).

Now I am thinking that I should try to bypass EGR completely for testing. If I got it correctly it should be possible to block the vacuum hose at top of the EGR valve to keep the valve closed. Then the car would act as no EGR, right?
 

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Tested to remove EGR valve hose, made no difference.

Replaced O2 sensor, no difference.

Tested with another MAP sensor, no difference.

When I look at my intake manifold gasket it looks wet. Could that cause a vacuum leak even though cannot notice anything when sprayed with throttle body cleaner on it while idling? Of course from bottom side can't test it really because no space.
 

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Tested to remove EGR valve hose, made no difference.

Replaced O2 sensor, no difference.

Tested with another MAP sensor, no difference.

When I look at my intake manifold gasket it looks wet. Could that cause a vacuum leak even though cannot notice anything when sprayed with throttle body cleaner on it while idling? Of course from bottom side can't test it really because no space.
Wet with what?
 

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Wet with what?
Not sure actually. Does not look like fresh oil (valve cover gasket had been leaking before I got the car). So could it be something related to gas. Even though there is underpressure in manifold could it still leak outwards? The replacement does not look too simple with the limited space, but I guess it is not impossible if not need to hurry it in one evening...
 

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Same type problems here. 1996 Camry 2.2L 5 speed. The car jerks really bad when the engine is cold and a lot of throttle is applied at low RPM. It does not do it when the engine is at operating temp. It has to be engine temp fuel related.

When it is cold and I only open the throttle a little at low RPM it wont do it. If it is at high RPM it won't do it regardless of throttle position. But if I jam the pedal down on a cold engine at low RPM the engine will just cut out, come back with power, cut out and just keep in this cycle until I almost completely close throttle. I also notice that on a cold start, the engine will fire as normal but then the RPM's will momentarily drop way down just about until the engine quits for a second before coming back up.

No engine light comes on with this. I tried to diagnose with the engine light per the service manual but both diagnostic connectors (Engine compartment and under dash) are missing the pins to activate diagnostic mode. (No wires from the factory).

I cleaned the throttle body but no results.

Problem is annoying. Interested if anyone can figure it out.
 

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Hello all,

As the title states, I have a 1999 camry, 4 cylinder 2.2l. For a while now, the car has been doing this thing where it bucks/jerks when in low gears. It only does this when I step abruptly on the gas, or abruptly let it go. It is especially noticeable when the engine is cold. I haven't been having any real problems with the car. It idles fine, and the engine sounds fine, but this little problem is kind of irritating.

Like I said, when I'm traveling at higher speeds it's not a problem. Also, after the car's warmed up it's not as noticeable (but you can still tell it's there). Has anyone experienced a problem like this, or have any idea what it might be?

I appreciate any and all help.
I had the same problem with my toyota camry 2012 automatic. Valve body of my transmission was jammed and they fixed it and now it is good. It could be expensive
 

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Not sure actually. Does not look like fresh oil (valve cover gasket had been leaking before I got the car). So could it be something related to gas. Even though there is underpressure in manifold could it still leak outwards? The replacement does not look too simple with the limited space, but I guess it is not impossible if not need to hurry it in one evening...
Was there any resolve for this? The suspense is killing me. What a bear of a problem.
 
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