Engine Trouble on gen4 Camry

[seraslibre]

I have a 99 4cyl camry with 100k mi. Recently, it has started to give me some problems I can't seem to track down. I assume they are all related, so I will list them in order of recurrence, from most to least:

1. Throttle gets stuck when engine idles. Takes an above-normal tap on the accelerator pedal to get it to open. When the throttle is opened (accelerating from stop) the engine first revs down, about 50-100 rpms, then proceeds to accelerate. This is usually followed by a faint smell of gasoline. Throttle acts normally once car is moving( e.g: I can lift my foot off the accelerator when the car is moving and upon pressing it again, the throttle opens freely). Note that throttle sticks only when car comes to a stop. Also, when car is off, throttle no longer sticks.

2. Under hard acceleration, smoke is emitted from the exhaust, followed by a faint smell of gasoline.

3. Engine will idle at very low rpms (~450) when it should usually idle at 800-900 during a cold start. I usually accelerate it myself for a few seconds until car holds "normal" idle on its own.

4. When under moderate, constant load (e.g. going up a 5 degree incline) the engine will hold a "controlled" but unusual aceleration/deceleration trance where it will rev between ..say 2100 and 2150 rpms...up and down, continuously, until load conditions change (e.g. harder acceleration or deceleration).

5. Least common, but most bothersome of all symptoms, the engine will run harshly, causing the transmission to go out of whack and shift between 3rd and 4th gear sporadically..while under constant load, until load conditions change. The engine seems to want to stall..but runs smoothly for a half second when about to stall...then repeats the cycle.

I have changed some parts upon scanning through the forums here, to no avail. So far, I have replaced the engine temp sensor, throttle position sensor, fuel filter (10kmi), spark plugs and wires, and, as preventive maintenance, I recently replaced the timing belt and water pump. The car does run better after all these new parts, but not as good as it did 2k mi ago. I like my camry and would hate to get rid of it. Any and all help will be greatly appreciated.

BTW: This car is not a neglected child...it has been well taken care of since i purchased it 2 years ago with 36k mi

[Nick]

idle air controler or O2 sensor???


that's my stab at it

[Aussie Ed]

i think i have a possible solution for problem 1. get the throttle body cleaned of carbon deposits.

the rest, i don't know.

[kocho]

Originally posted by Aussie Ed
i think i have a possible solution for problem 1. get the throttle body cleaned of carbon deposits.

the rest, i don't know.

I second that - had the same problem - the gas pedal would stick while the car is in park (at a red light for instance) and I'd need to tap the gas pedal.

Clean the throttle body with the spray-cleaner and a toothbrush plus some good rags (that do not leave lint and pieces behind). The cleaner sells at Toyota dealerships too and costs about $3. You only need a philips head screadriver to losen one screw on the inteake to remove the hose to get access to the throttle body.

Move about the throttle plate so you can reach behind it. Follow the instructions on the bottle and you'll be fine.

If you are not the hands-on type (e.g. one screw to remove is too much and brushing your own theeth is a hard chore , because it is about as difficult to clean the throttle body ), then go to the dealership or another place to get the throttle body cleaned. I think that unless you have the gas cable stuck somewhere, this should solve your first problem.

To address some of the other problems, use some fuel injection cleaner (Berryman B12 is what I used) to clean your ingectors (you pour this stuff in your gas tank). Drive till you empty one tank of gas (not necessarilly without stopping ), occasionally revving the engine up to 4-5K for a few seconds to help with the cleaning. Then get back to us to let us know what happened...

[seraslibre]

Thanks for the advice guys. I will clean the throttle body tomorrow and follow it with a shot of injector cleaner in the gas tank. If anybody else has further suggestions please do not hesitate to add them.

Thanks in advance.

[kocho]

Originally posted by seraslibre
Thanks for the advice guys. I will clean the throttle body tomorrow and follow it with a shot of injector cleaner in the gas tank. If anybody else has further suggestions please do not hesitate to add them.

Thanks in advance.

For the fuel injector cleaner, use either Berryman or the stuff they sell at Toyota (forgot the name, but I think it is Techron or something like this). People have reported good results from either of these.

As for the throttle body cleaner, make sure it states it is safe for O2 sensors.

[dj14901]

Lucas fuel injector cleaner is also very good...

DJ

[ryan7373]

try redline sl1..... good stuff.

ryan

[seraslibre]

...update

OK guys, I added fuel injector cleaner to the gas tank, cleaned out the throttle body, and removed some deposits from the upstream O2 sensor. Performance did improve, but only after I went to AutoZone and got the OBDII codes cleared. The only problem that persists is an ever-so slight reocurrence of the surging/hesitation described earlier, and very infrequently.

Thanks for all your help..now I can enjoy my ride for another 150k mi!

[kocho]

Originally posted by seraslibre
...update

OK guys, I added fuel injector cleaner to the gas tank, cleaned out the throttle body, and removed some deposits from the upstream O2 sensor. Performance did improve, but only after I went to AutoZone and got the OBDII codes cleared. The only problem that persists is an ever-so slight reocurrence of the surging/hesitation described earlier, and very infrequently.

Thanks for all your help..now I can enjoy my ride for another 150k mi!

Good to hear!

[seraslibre]

..bad news again...

unfortunately, the check engine light came back on and the car is running the same as it was before, only that now the accelerator does not get stuck when at idle. The car does not idle smoothly, it revs up and down about +/- 50 to 100 rpm when idling, and there is slight surging/hesitation that is barely noticeable at times when accelerating. When I went to autozone to get the codes cleared, there was a MAF (mass airflow) error code. I know that the 4cyl camry does not have a MAF sensor, so did not know what to attribute this code to. Also, there was a "bank 1 lean"error code.I keep close track of my fuel economy, and it has gone down to about 19mpg from 27mpg before all these symptoms appeared. If anyone can help it will be greatly appreciated. I like to have my car running in tip top shape....and honestly did not expect this from a camry with merely 100k mi.

[csaxon]

How old are your spark plugs/ air filter/ fuel filter? I'd run a few bottles of techron or bg44 through the system for awhile and see if things improve. There were some complaints on other boards of users with aftermarket plugs having similar symptoms. They went back to the original ( I think Denso plugs) and the roughness disappeared.

[fe519]

what year is your car? if its a '99, correct me if im wrong, but there is a maf sensor on the intake. also, after you sprayed the throttle body cleaner, the car will blow a lot of smoke and is hard to start. when i do it, sometimes there will be a CEL, but only when i spray a lot in there. just make sure you clean the throttle body and the surrounding areas.

[fe519]

the idling might be your idle air valve... extremely common in the 4 cyl.

[basco16]

Had the same problem on my 97 camry.
The Gas pedal would appear jammed when I'm at at stop light.
Used Throttle Body cleaner & a toothbrush & cleaned out the gunk.
It's as good as new now. Solved the problem.