1989 Tercel Acceleration (Carburetor O-Rings? Carbon in Intake?!)

I have a problem with my '89 Tercel. When I accelerate, but the torque of the acceleration is hindered at first, like not enough/too much gas is getting to the engine, and if I keep the gas pedal lightly pressed, around 2500-3000 RPMs, the car will suddenly gain torque, and I’ll have some power behind the engine. If I push hard on the accelerator, the car seems flooded, and then jumps to 3000-4000 RPMs. It isn’t as noticable in 3rd or 4th (probably because I’m consciously shifting at a higher RPM to avoid the problem) unless I’m going up hill.
I have read a number of forum posts on this problem.
Half say it’s a problem with carbon in the intake/outtake manifolds of the exhaust. The other half say it’s a carburetor problem regarding the o-rings.
I’m a new owner of the car. It has 210,000 miles, and I’m not sure if it has sat for a while.
Just trying to get 20th opinions here.
Any help is appreciated.

You may disregard the but in the second sentence. (blushes)

The 89 Tercel is fuel injected, so carburetor problems are out of the question. I would have the O2 sensor checked, it is not monitored by the computer. There should be a 2 pin connector near the distributor that has a cap on it. You remove the cap and use an analog voltmeter on the two pins to see if the voltage sweeps between 0-1 volt about every few seconds.

The carburetor would be my first guess. Your car has a different type of carburetor, it’s called a “variable venturi” carburetor and will require someone familiar with this type of fuel system to properly diagnose and repair.

It sounds like a too-lean condition. At 210K miles, could be caused by lots of things. You may simply need a replacement carb (if you car has one, from the posts above seems ambiguous). My first guess would be a vacuum hose or device leak or a faulty EGR system.

Do you have the factory shop manual or a Chiltons for you car? That would be a place to look to for inexpensive diagnostic advice for this problem.

If this Tercel was sold in the US, then it has a 4AFE engine which is fuel injected, not carbureted. The 4AFE was a smaller, detuned version of the famous 4AGE engines of the popular AE86 Corolla’s. The last Tercel with a carburetor was the 88 4WD wagon and it had a progressive two barrel carburetor, not a variable venturi. All other Tercels got the fuel injected engine starting in 87. All his symptoms point to the oxygen sensor.

89 and 90 had carbs. overhauling VV carb on one today . Several things could be causing the issue . Make sure venturi slide is free and opening as RPM increases .

I would hope after this much time the Original Poster would have solved their problem.