2001 Camry 2.2 acceleration hesitation & jerking

I hope someone can help guide me in the correct direction… money is tight, so I cannot afford to start indiscriminately replacing parts.

I drive a 2001 Toyota Camry LE, 2.2 4 cylinder. It has about 206k miles on it… About 2 months ago I started to feel slight hesitation when I was driving…. It was so slight I wasn’t sure if it was happening or not. Recently the hesitation has become much worse… typically it will hesitate and jerk when I try to accelerate from slow speeds… this primarily happens when the car is cold. It will also jerk and hesitate when I am cruising at a fixed speed. If I step on the gas, the jerking stops.

Here are known issues and recent work I have had done… in November I replaced my complete exhaust system myself, including the downstream oxygen sensor. The cat is now bad and it will rattle. I had a mechanic replace my water pump, timing belt and all pulleys and tensioners associated with it about 2 weeks ago. The hesitation predated this problem.

About 5 years ago I replaced my own plugs and wires… when I did this; I noticed oil on one plug. This was for the cylinder closest to the driver’s side. I never noticed any issues with the performance of my car related to the oil, and I do not burn through much… perhaps a quart every 2 months. About a week ago I replaced my plugs and noticed the oil again. I do not know if this relates to my hesitation problem or not. I also filled my tank and used a container of injector cleaner, thinking perhaps a clogged injector was causing the problem.

The problem still exists.

Now I am thinking it might be one of two problems… either a defective ignition coil or a bad throttle position sensor. Yesterday I borrowed a code reader… it told me I had “long fuel trim in bank 1”.

Can someone please give me their thoughts? I really cannot afford to dump a lot of money into my car.

Thank you,

what was the code number?

P0420 – it’s listed twice… once as that and once as pending.

P0420 Toyota - Catalyst System Efficiency Below Threshold Bank 1

found online:
As the code description implies the P0420 code means that the vehicle’s control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic convert needs to be replaced to fix the problem.

I know I have a bad cat… but could the bad cat cause these problems?

yes, those are consistent with a clogged cat.

ok, thanks.

Could you give the actual DTC for the “long fuel trim in bank 1”?

I am wondering if you have air leaking into the exhaust manifold ahead of Sensor 1 Bank 1, i.e. the upstream O2 sensor.

There was another person here who had similar symptoms. I think her car was a Toyota too. At last report as I recall she had solved the problem by a shop cleaning the fuel injection system.

There’s many other things that could cause this symptom. But if the fuel injectors are a little clogged this symptom can result. When clogged they have a difficult time regulating the amount of fuel injected at low fuel usage. Like a garden hose nozzle that is clogged, it will work ok at full force, but does weird things, sprays every which way, if you adjust it to spray a trickle.

But before deciding one path or another, as mentioned above, post the diagnostic codes stored in the ECM memory.

Long term fuel trim isn’t usually a code for a problem. It is a feature that allows the code reader to read the ECM’s long term fuel trim measurement. The ECM expects for given condition a certain amount of gas needs to be injected. The LTFT parameter is how the expected amount differs from what it actually needs to inject based on the O2 sensor reading. If an injector is clogged, it will think it is injecting more than it actually is with each injector pulse, so the O2 sensor will read “lean”, and the ECM will have to inject more gas. It will that register extra gas beyond expectation to meet the O2 sensor as a LTFT measurement.

Edit: Unless you drive a lot of miles per month, having to add a quart of oil every two months isn’t the norm. You have some kind of oil usage or leak problem going on too.