1999 Camry v6 bucking/hesitating

All,

I have a strange problem. When driving my 1999 camry at a steady speed it seems to buck or hesitate slightly. However when I accelerate, it goes away. It just happens when keeping the care at a steady speed and it happens all the time. Any suggestions?

Thanks,

Reply to
Honda-Man
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if it just started-could be water or something in the gas next fill up and it will pass- \

If it is longer than that--I don't know

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Reply to
M.Balarama

You need a car whisperer.

Reply to
Mark A

Yeah, thought you were riding a horse.

It's hard to tell the source of bucking and hesitating. Might want to find out if it's a plug miss or EGR malfunction.

Check your local AutoZone and see if they can pull any hidden codes from the OBD-II system with their free service. These hidden codes don't light up the MIL light yet, but may be in the system especially for plug misses. (Of course I don't recall at the moment if the plug miss condition is met in your case to set the code or turn on the MIL). Toyota OBDIIs aren't very good or accurate at EGR or EVAP system codes.

Reply to
johngdole

I have a 97 Camry 4 cylinder and noticed that phenomenon, forget about it, it's an attribute of the car.

Reply to
<psommerhalder

Good thought. I will try that.

Thanks,

Reply to
Honda-Man

at a steady speed and it happens all

== Those are conditions of maximum EGR use. I'd check there first.

Reply to
Daniel

I have noticed this on several cars - slight hesitation at part throttle

- mostly when one eases on the accelerator very slightly. I suspect there's a way to stop this by messing with the fuel mapping but it might be what's seen as an acceptable penalty for higher MPG figures. And that's as good a rational as any, for me, at least. :-)

david

Reply to
dsi1

All,

I have solved the problem I posted, and I am a little ashamed at the same time. This past weekend I went to start my car and nothing happened, then tried it again and it started. I checked the battery and found the positive post to be excessively corroded under the red plastic cover. I took the connector off and cleaned it well including the battery post. The car starts and runs perfect now, NO MORE HESITATION! The lack of battery juice must have been causing the bucking and hesitation.

Thanks to all for your suggestions.

Reply to
Honda-Man

Reply to
<psommerhalder

Interesting solution. Usually the alternator comes up with enough juice. Better clean my sparkling battery posts again.

Reply to
johngdole

Normally, the alternator does have enough juice to power your car once it is started, but a battery with a positive connection that leaks to ground because of corrosion can act like a "black hole" and suck up current from the entire electrical circuit.

But even if the battery is OK, think of the battery as a UPS for a computer. It keeps the current constant during momentary fluctuations in the power. Considering how many times your spark plugs ignite (about 50 times per second under normal driving), even the slightest loss of constant power from the alternator will cause problems. If cars did not have batteries, then they would need large capacitors (like electronic equipment) to maintain constant DC current.

Reply to
Mark A

Yeah, I notice those large caps on circuit boards are getting larger.

But difficult to believe than even a 90amp alternator working at 30% capacity can't feed Honda-man's Camry. Now I wonder what plugs were used and when were they last changed? I use exclusively NGK Iridium - IX or -Laser on cars I help work on.

Reply to
johngdole

It is not a question of whether it can "feed" the plugs. It has to do with momentary (milliseconds) lapses in DC current. If we were talking about AC, that would be different, but DC circuits typically require some kind of battery or capacitor in the power supply. This is especially true with cars that have computer controlled electronic ignitions (all modern cars).

If you hooked up your desktop computer to a DC alternator without a capacitor or battery (bypassing your AC to DC power supply), it would constantly be rebooting.

Reply to
Mark A

Great conversations, and very informative. In regards to my spark plugs, I replaced them with bosch four prongs ($4.50 a piece) , since I thought the plugs may have been the reason for the hesitation. I now know that Toyota prefers NGK and will use them in the future.

Reply to
Honda-Man

Thanks - I've noticed this in several cars but it could be that the additional .5% drop in MPG figures that it would take to make your car run smoother is unacceptable. My guess is that when we get to throttle by wire systems this effect can be eliminated. Of course, this is all speculation. :-)

david

Reply to
dsi1

One owner here uses the Bosch x2 and seems to be happy with them. Both the Bosch's and NGK's thin electrodes should help lower voltage demands. But Mark was saying that it's the DC current lapse. Well, it's getting above me so I just leave it at that. I just leave my battery with periodically cleaned posts in there ;-)

BTW, I'd stay away from the Denso plugs, which Toyota also specs. IMO they're not as good as the NGKs.

Reply to
johngdole

Hey, now Toyota's Lexus ES350 (equivalent to Camry V6) is having sudden acceleration problems. So maybe those owners rather have the hesitation problem, you think? ;)

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"Federal regulators have stepped up an investigation into 98,454 Lexus ES 350 sedans after amassing 40 reports of unintended acceleration, including eight crashes and 12 injuries, along with cases in which drivers said their cars stopped only after an accident."

Reply to
johngdole

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