Please help 89 corolla 4af engine 1.6 dohc

[djbahlmann]

Hello all!
I have an 89 corolla LE 5spd 1.6 dohc carburated. It's last tune up was 20,000 miles ago, plugs, wires, fuel filter, cap, rotor. It slowly started to have a bit of a hesitation on 1/4 acceleration about a year ago, now it backfires through the carb and bucks and kicks, on acceleration once up to speed it is fine untill you try to push on the pedal again.if you keep the rpm over 2000 it does not do it, it only happens from 900 to say 1500rpms.
Any thoughts would be great. Just for the record when it was tuned up I used a Chinese made distributor cap, (I know Sorry ) I found a Japanese cap but not sure if this is the problem, the one on it had a lot of corrosion on the contacts, I cleaned them, it then seemed to take the problem away, but came back after a mile!
Thanks, everyone
Darren B.

[RickMN]

Moisture in the cap, a crack in the cap, or a poor quality cap can cause all the backfiring, bucks and kicks you're talking about. Since you're due for a tune-up in the near future anyway, why not replace the cap and rotor with a name brand. Have you checked the gap on the plugs? How are they burning?

When was the timing belt changed?

Backfiring through the carb is a serious problem. If can be cause by ignition issues, timing belt off a tooth, or a sticking valve. Of those possibilities, the least expensive and easiest to fix are the ignition problems. My advice, replace plugs, wires, cap and rotor.
Write back and tell us if that helped.

[djbahlmann]

Hey Rick,
Thanks for the quick reply! I did order a new cap and wires they are about $90! they are from Napa and the guy said they are made by Toyota out of Japan, so this has to be a decent set.The old set was made in china and was around $40. My timing belt is good, however I have not adjusted the valves on this for about 20,000 miles, it is getting 38mpg on average, not bad for a carbed unit, with 245,000 miles to boot!! Fuel filters are good, I used NGK plugs in it also when I tuned it last.
Thanks again for your help.
Darren

[djbahlmann]

Hey there Rick,
The new distributor cap worked! I also replaced the plugs and rotor, timing was good. I am surprised how bad it ran, specially with a full tune up only 20k ago. Thanks again for your help, I appreciate this web site it sure is helpful with the knowledge of all of you!
Take care, Darren