Celica Forums General Discussion Engine and Performance Hesitation around 2100rpm? 2002 Celica 140

Hi all,

Have had my 2002 Celica 140 for around a month now.

Cracking car, fun to drive.

The only niggle that is really annoying me is this.

Around 2100-2300rpm, the car hesitates and kangaroos slightly.

Almost as if it is running out of fuel.

Below this, it runs well, above this it runs well to the redline, no other performance issues.

I've changed the spark plugs, oil change, cleaned the MAF, throttle body and the IACV.

It seems to be most noticable when the air conditioning is on, which puts a bit of strain on the engine. It also fluctuates the idle between 700 and 1100 rpm. Not sure if related.

One thing that might be related, is coming off the accelerator pedal in this range, it takes it a second to 'kick in' and start dropping the revs.
Probably not even a second, but there is a very slight delay here.

Anyone experienced anything like this?

I was thinking maybe a flat spot in a throttle potentiometer, but the Celica doesn't seem to have one.
Then I was thinking maybe engine mounts?
Would these go after 80k?

Thanks

Noticed it occuring this morning in 30mph traffic around 1600rpm with the AC off. Not quite as noticable as the chugging with the AC on at 2100-2300, but still there.

I've found where the throttle position sensor lives, logical place, clamped on the side of the throttle body (D'oh!). I might check the voltages through it.

Would it have a Pedal Position Sensor?

It really feels like something like this, when feathering the throttle at these RPMs, the voltage might be alternating between the slight signal, and 0, causing the ECU to think the throttle is engaging and disengaging.

Thinking maybe Ignition coil?

Noticed when changing plugs, the coil nearest the oil filler cap, the round disc was slightly snapped. The rubber seal was still present.
The boot itself was a bit oily, presumably an oil topup spillage and some had found its way though the snapped part of the circle.

I took it out, cleaned the oil off it, swapped it with the 1st coil furthest from the oil filler cap (to prevent this occurring again).

Slight misfire/hesitation/kangaroo still exists around 2100rpm or so, so hasn't cured anything. But was thinking maybe replacing this entirely might help matters.

could be the belt? since the ac runs off the belt