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Discussion Starter #1 (Edited)
Help. Camry jerks under moderate or heavy acceleration. Update II: Problem returned

Last week my 2000 Camry I4 with about 216,000 miles, began jerking whenever I accelerate moderately or aggressively. If I lightly accelerate I do not usually get the jerking. Also the jerking is more pronounced when accelerating up a hill. I usually don't get the jerking going down a hill. The jerking occurs in all gears.

I do have a P1780 PNP Switch Mafunction error code. It was on for a month before the jerking began. I don't think it is related. I may be wrong. No other error codes or pending error codes

I cleaned the throttle body and the IACV after the jerking began.

I put new gas in. Also added Chevron fuel system cleaner. No change in the jerking.

The transmission fluid is clear, clean, and light red. I do a drain and refill every 25,000 miles. Also the transmission seems to shift smoothly.

New spark plugs about 35,000 mile ago.

I'm thinking of replacing the fuel filter. It's probably time to do that anyway.

Any other ideas on where to begin to troubleshoot this problem. Thanks for your help.

Update: Problem solved. Replaced spark plug wires with NGK RC-TE58. Works great now.

Update II: Problem has returned. See post number 10
 

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First thing that came to mind was the fuel filter. Let us know if that did the trick.
 

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Plug wires, perhaps?
 

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Discussion Starter #5
I replaced the fuel filter That did not fix the problem.

If I put the transmission in drive and hold the brake down, then press the accelerator the engine will sputter. If the car is in park and I press the accelerator the engine just revs up.

I guess I'll try plug wires next.
 

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I had a car years ago that had the same symptoms and replacing the filter did the trick. Good thing in your case that the fuel filter is cheap and needed to be replaced anyway, so no harm done for your car there. Do let us know what else you try (like ignition wires) and if that did work out.
 

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Discussion Starter #8
Problem solved. Replaced spark plug wires with NGK RC-TE58 spark plug wires. Works great now. Thanks for all the suggestions and help.

Here's some additional information concerning the symptoms of my problem: This winter, my Camry would not start unless I held down the accelerator. I assumed it was the IACV. I was just living with the problem because I had previously cleaned the IACV. Last week I cleaned the IACV after I was experiencing the other more severe symptoms. After cleaning, my Camry would start without holding down the accelerator but the idle was low, about 500 rpm, and I did not get the fast idle on start-up.

After changing the spark plug wires I'm getting the fast idle and am idling at 750 rpm.
 

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So, again we see that BMR can solve all of our problems!:clap:
 

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Discussion Starter #10
Problem has returned.

Thinking it could not be the spark plug wires, my first thought was the connectors. I checked the connections. I found one connector that had some sort of corrosion/ carbon on it. I cleaned both the male and female parts of the connector with alcohol. Also when I was pulling off the connectors, the connector with the corrosion/carbon came off easily. Maybe I did not get it fully seated when I replaced the wires.

On my test drive there was significant improvement but I still think there is a some jerking. I'll have a better idea tomorrow after I drive it tonight at work.

One additional symptom is that the jerking gets worse over time. I thought I noticed some jerking on Wed. The jerking was so infrequent I was not sure it was even jerking. By Fri there was significant jerking.

Does anyone have any thoughts?
 

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Inspect the ignition coils (your 2001 has two) for cracks. There are also resistance checks you can do. Sorry, I don't know the specs for your year.

Coils often "act up" when they're hot. Is there any tendency for the misfiring to be worse when hot?
 

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Discussion Starter #12
I drive my car about 3.5 hours every weekday morning. Like I said before the jerking gets worse over time. The jerking is usually worse at the end of my drive than at the beginning. I didn't correlate that with the coils heating up. I'll pay more attention to that aspect.

How long would it take for the coils to heat up enough so they start acting up?

My coils are pretty dirty. It will probably be hard to see any cracks. I noticed coils are not too expensive. Once I'm convinced they are the likely culprit maybe I'll just swap them out one at a time and see if that makes a difference. At first glance doesn't look too hard to do.
 

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You can remove the coil packs, clean them, and then test them with an OHM meter, or look for cracks.

Remove the spark plugs and check the tips, keep track of which spark plug comes from which cylinder:
Google: spark plug condition

See what it tells you about general running conditions(lean, rich, oil) and if only 1 or 2 cylinders are giving you the problem, i.e. one coil pack is mis-firing when warm.

Coil temperature would have alot to do with RPM and outside temperature, stop and go driving will heat up engine compartment more and warmer outside temperature will mean a higher average temp in the engine compartment, high RPMs heat up the coils faster.


All Fuel Injected engines have what is called a "clear flooded engine" routine, it is:
Turn key to RUN(on)
Press gas pedal to the floor and hold it down
Turn key to START(crank engine)

Engine should not start, with gas pedal to the floor the computer sees WOT(wide open throttle) voltage from TPS(throttle position sensor), this tells it to turn off fuel injectors to "clear flooded engine", but spark stays on.
If you release the gas pedal while cranking, the engine should start because injectors will start up again.

Reason I mention this is because of your hard start problem in the past.
A leaking injector can flood a cold or warm engine making it hard to start, turning off the other injectors can balance the fuel/air mix enough to get engine started.
MPG would show a noticeable drop with leaking injector.
 

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Discussion Starter #14 (Edited)
Update: Problem seems to have been solved. After replacing the ignition coils and spark plugs, the jerking has seemed to stop. Replacing only the coils appeared to have no noticeable affect on the jerking.

I'm embarrassed to admit this but the reason I did not replace the plugs earlier or check them was the last time I installed them I used my new torque wrench. Normally, I just hand tighten and had never had a problem removing them. I had previously tried to remove them and I was unable to get them out. I thought I might have mistakenly over-torqued them. Anyway, I had just taken the Camry out for a test drive after changing the coils. Then it occurred to me that the last time I had attempted to remove the spark plugs the engine was cold. Now the engine was hot and maybe the spark plug holes had expanded. Lo and behold, I was able to get them out with some effort.

So I replaced the old spark plugs with NGK Iridium plugs. I could immediately tell that the engine was reviving higher on start-up. I took that as a good sign. It appears it was. Did not have any jerking on the test drive.

Also, the old spark plugs appeared normal.

I've only taken a short 10 minute test drive. I'll update next week after I drive it for longer periods of time. Thanks again for everyone's input
 

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So I replaced the old spark plugs with NGK Iridium plugs. I could immediately tell that the engine was reviving higher on start-up. I took that as a good sign. It appears it was. Did not have any jerking on the test drive.
So the old plugs with only 35k miles on them were likely bad? Wow. What brand were they?
 

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Having similar problem here with a 2009 camry 2.4. Any sudden high-throttle demand usually causes a jerky acceleration. The RPMs bounce up and down in sync with the jerking. It feels if I'm jabbing the accelerator in and out, but my foot is steady holding throttle open as this behavior takes place.

I've replaced coolant sensor, plugs, coils, air-filter, MAF, fuel-pump and injectors. I've done valve cleaning, crankcase flush, tranny drain & fill, fuel additives. I don't get any codes either.

The only thing I can possibly think of is perhaps the TPS is going bad - or a small conspicuous vacuum leak somewhere down stream of throttle body? But if this was so, shouldn't I be seeing a code by now? LTFT remains around +3.

Seems to happen when there's any abrupt demand for high-rpm....

Maybe I should start a new thread and should not have posted here. I'm all-ears for ideas at this point.
 

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Doesn't the '09 use electronic Throttle Body / Gas Pedal ?

Testing the electronics on both according to the FSM / visually inspecting connectors & wiring ... for any cuts/chaffing/corrosion/etc. would be a primary diagostic, if happening here.
 

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Doesn't the '09 use electronic Throttle Body / Gas Pedal ?

Testing the electronics on both according to the FSM / visually inspecting connectors & wiring ... for any cuts/chaffing/corrosion/etc. would be a primary diagostic, if happening here.
thank you for your response.
yes it uses an electric tb. Before getting the volt meter out, etc I happen to have an extra working oem throttle body I have not used before. if it's indeed a TPS issue, replacing the throttle body with a known good throttle body should fix the issue, right?
 
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