1992 Camry Hesitates

[Brian90638]

My car: 1992 Camry, 4 cyl, automatic, 266,000 miles.

About 4-5 months ago I was driving on the freeway at about 65-70 miles an hour and slowed down for heavy stop and go traffic. Upon coming to a stop the car nearly stalled. Each time I barely pressed the gas peddle to move forward in the stop and go traffic the car would nearly stall. I exited the freeway and tried to recreate the stalling in a parking lot but it ran fine. I was able to make it home no problem. The next day I tried to recreate the near stalling again and the car seemed to operate fine until it got warm.

I took the car to my mechanic and he could not recreate the issue or find a problem.

The car still has the problem and I can't seem to determine what it is. The car is tuned up fine and otherwise runs great. With my Haynes repair manual I have checked several items and still can't determine exactly what's causing the issue.

Here's exactly what happens; I start the car just fine. The car idles fine and smooth at 800-900 rpm. In park or driving I press the accelerator slightly to bring the rpm's up slowly. When the rpm's exactly reach 1,500 the engine nearly stalls and the rpm's drop to approx 500. I let off the accelerator and the car returns to idle fine. If I continue to press the accelerator during the rpm drop it will recover but sputter until 2,000 rpm exactly. The car runs perfect above 2,000 rpm. After checking this repeatedly the car only hesitates/sputters between 1,500-2,000 rpm. All other rpm conditions are normal. On occassion I notice an unburned fuel smell coming from the exhaust but not always.

With my Haynes repair manual and this forum I have checked the following;

1. I disconnected the MAP sensor connection and the car almost stalled at idle. Check engine light comes on. Reconnect sensor and car idles perfect.

2. I disconnected the "Coolant temp sensor" and car idles horrible. Check engine light comes on. Reconnected it idles perfect.

3. I disconnected the upper oxygen sensor on the exhaust manifold (single wire) and there is no change in performance. No check engine light comes on.

4. I disconnected the lower oxygen sensor on the exhaust manifold (2 wine) and there is no change in performance. No check engine light comes on.

5. I have cleaned out and checked the "EGR Vacuum Modulator" and connecting vacuum lines and there is no change in performance.

6. I have checked for trouble codes using a jump wire and get no codes indicating no known problems.

7. I intend to clean out as much of the throttle body with carb cleaner as I can today to see if that helps.

My thoughts are the problem may be with one of a couple things;

1. EGR Valve has gone bad. Can this be cleaned or must it be replaced?

2. Upper single wire oxygen sensor bad?

3. Lower 2 wire oxygen sensor bad?

If you have any ideas, things I should check, or thoughts I'd appreciate your response.

Brian

[Brian90638]

Update:

I removed the intake air filter assembly and sprayed about a half a can of carb cleaner in the throttle body. A lot of dark brown residue came out. I disconnected all of the vacuum lines I could and cleaned them as well. Blew it all out with compressed air and waited a while to make sure most of the carb cleaner had dried out.

I re-assembled everything and much to my surprise much of the carb cleaner had not evaporated because it traveled down the throttle body and into the cylinders. Car wouldn't start at first and it concerned me because I thought I had messed something up. I kept trying and it finally started very rough. Once started tons of blue smoke came out of the exhaust for about 4-5 minutes. Car ran good though.

Anyway, I took it for a test drive and the condition was much improved. 99% better. The hesitation is super minor now and almost not noticable. It is however still there. Which leads me to believe I was on the right track with the cleaning. Next I think I will remove the IAC and the EGR and make sure those areas are clean where they meet the throttle body.

[94camrycoupeSE]

I have a 94 camry V6 with 220K miles on it. It also started hesitating in the morning usually between 3000 and 4000 rpm. The higher I revved the more it hesitated. I bought a can of throttle body cleaner and mass airflow cleaner. I removed the cold air intake pipes off the throttle body and held the throttle open manually while spraying into the throttle body. With a clean towel I wiped inside as far as I could reach. The towel came out black. I continued spraying the throttle body until it was mostly clean. I then sprayed the mass airflow sensor a bit with the mass airflow cleaner. I think the sensor is a vortex type so only a few sprays was necessary. Everything was put back together. When starting the engine, I held down the gas so that the engine would start. I did this at night because lots of black and blue smoke will come out of the exhaust. I kept the engine revving at around 2500 rpm for a few minutes until all the throttle body cleaner burned off and then took the car out for a drive. The engine felt strong and no hesitation. I'm sure this engine will last me another 100K+ miles easily.

[Brian90638]

I have a 94 camry V6 with 220K miles on it. It also started hesitating in the morning usually between 3000 and 4000 rpm. The higher I revved the more it hesitated. I bought a can of throttle body cleaner and mass airflow cleaner. I removed the cold air intake pipes off the throttle body and held the throttle open manually while spraying into the throttle body. With a clean towel I wiped inside as far as I could reach. The towel came out black. I continued spraying the throttle body until it was mostly clean. I then sprayed the mass airflow sensor a bit with the mass airflow cleaner. I think the sensor is a vortex type so only a few sprays was necessary. Everything was put back together. When starting the engine, I held down the gas so that the engine would start. I did this at night because lots of black and blue smoke will come out of the exhaust. I kept the engine revving at around 2500 rpm for a few minutes until all the throttle body cleaner burned off and then took the car out for a drive. The engine felt strong and no hesitation. I'm sure this engine will last me another 100K+ miles easily.

Mine is 99.9% better but I am going to take a little more time on it in the coming weeks.

[Broadcaster]

My Solara 1999 116K miles displayed similar symptoms

A trip to my trusted mechanic he said "I know what this is give me half an hour"

He sprayed something into the throat of the car and started it up

A lot of black and blue smoke and the trouble was gone.

Later over lunch he said it was "Slow idle setting " or words to that effect. "You will have no trouble for at least a year"

This was about 4 months ago. So far so good

Please meet my emergency taxi driver (A Russian immigrant) Mr. Pikop Andropof who is rather a bumpy driver.He helps me when the car is in the shop for more than two or three hours. Admittedly not that often.

[Christoff Marcs]

The Camry is a bit dicey when it has problems. Really good thinking on your Toyota Camry repair. Removing the intake filter is quick thinking.

[jdfausett]

I know this was from a few years ago, but I figure this might be worth a shot. I also have a 92 Camry, and it is doing the exact same thing, right down to the exact rpms. I was wondering if you were able to figure out the cause, as I desperately need to travel across the state, but don't want to do it with my car doing this. I have seen how expensive the Idle Air Control Valve and a new EGR valve are, and before I take it to a shop, I would like to try a few things.

Thanks so much!