92 toyota camry 4 cyl help please!

[mcrn]

At cruising speed the car surges, the RPM's fluctuate up and down about 100rpm with sluggish throttle response. Hesitant to shift. Car is automatic. It idles perfectly and runs great at full throttle. I have tried the 02 sensor, MAP sensor, the temp sensor, when I disconnect the throttle positioning sensor shifts better but still surges. Codes 25 have been thrown 1 time but has not sense then. The injectors have been recently replaced over 10K miles ago. New plugs, new cap, new rotor. Coil has about 10K miles. This is a friend of mine at work. Any help would be much appreciated. Thinking of replacing main PCU at this time. Thanks in advance.

 

[rg200amp]

Unhook the battery and let the computer reset. While thats being done, you may want to clean your Mass Airflow Sensor, and clean your throttle body.

Hook up the battery, let the car relearn, and see what happens.

I am sure some other folks will give you some other good ideas.

 

[Quest]

Check the plugs, caps, etc. to ensure that they are the correct heat type and also if possible, get the original Denso OE caps, rotors, Yazaki OE factory plug wires (or NGKs).

Check and see if your MAF sensor (vane type) has an open on the potentiometer part for given your vehicle's age, this may go. Also check to see if your throttle position sensor is at fault.

Q.

 

[mcrn]

Thanks guys but this model year with the 4cyl does not have a MAF.

 

[edge10]

I agree with checking the both MAF sensor and especially the TPS. The TSP is usually a potentiometer (variable resistor) that can be bad due to dead spots within its sweep range or out of spec through the range. A bad TPS typically causes hesitation at throttle tip-in and/or at another throttle position. I don't think you can really test the TPS by checking drivability with it disconnected. It senses throttle position and adjusted several power train parameters based its position. You need to either directly test the resistance or voltage output (depending on the Toyota spec) as you sweep it through the complete range from high to low. Any dead spots in the range will cause a problem. Code 25 might be a clue also. Good luck.

 

[Quest]

Sorry, mis-understood yours with Vee6 of the same era (that one comes with vane type MAF)

Q.

 

[mechtech2]

All vacuum lines need to be checked for leaks and cracks. Especially the PCV system. Really take a good look and trace each one. Any manifold leaks will cause problems also.
I'd clean the throttle body bore and plate also, at this time.
It sounds fuel related, not ignition.
There may be a coolant or air temp sensor out of range, or the TPS.

 

[mcrn]

Thanks guys, he says he has gone back and forth on the vacuum system on this thing. It is really weird. It seems like he has done everything. Thanks again!