Check the electrical connectors on the injectors by "gently" shaking them while the engine is idling. I had a corroded connector on one injector and it caused similar symptoms.
Check your spark plugs for cracks. Run your engin in the dark and look for arcing of
the plugs and wires. Don't forget to rev the motor to put it under a load.
Check for white deposites on your coil. This indicates that the coil is breaking down and electrcity is arcing to ground.
Also put some fuel injector cleaner in your fuel.
I had been having what felt like clutch slippage, kind of cyclic bogging down, in low revs. Car didn't lack upper end, or bother on hills though. I went through the bother of getting to the AIV, removing the top, and rinsing it out with electrical contact cleaner (its what I had, as I was also degreasing All contacts). (my speedo still wonk work right.) On removing the top clamp, the valve unit, was stuck. Some gentle pulling released it. The valve had to be stuck to some degree. Clean, bolt it back up, no bogging. Engine breaking smooth again. I feel (without real evidence) that this could be an additonal idle-type problem. I did have the unit replaced prior due to catastropic engine stalling when pushing the clutch and breaking. The unit seems to be easy to clean. I feel silly now for having it repla$ed.
Idle problems should include: MAF, MAF connectors, AIV, AIV connectors....
My 1993 would stop intermitently with very unstable idle and lack of power afterwards. Then after 5 minutes everything was fine. Dealer detected bad air flow meter, probably I could do it myself by reading error codes, didn't have time to do it. Got a meter form a dealer for $450.00 (why is it so expensive?), installation took me 30 minutes. Running OK so far.
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