Engine issue

[DRun]

I have a '98 4runner with 120,000 on it. Just recently, when driving 60-70 mph, the engine starts missing. I can't hear it making any unusual sounds but you can feel it hesitating. This problem doesn't happen all the time and so far it has only occured when driving at around 65 mph.
I have tried fuel treatments (Lucas Fuel & GXP) but niether have seemed to help.
Any ideas?
Thanks in advance.

 

[Kmvreter]

If you can't hear it but can feel it, could it be the tranny instead?

 

[wolfgang]

Have you tried new plug wires, plugs and distr cap? Still with OEM ones. If that doesn't help - it could be a cloughed injector. They can be removed and sent off for recalibration and cleaning. I've had good luck with Chevron Techron FI cleaner, A compression test would be good too -- you may find you have a low cylinder (due to valve, piston or head issue).