I know its long so i tried to give an overview with the pullet points, any help could be greatly appreciated

i recently purchased a vehicle that began displaying some unfavorable symptoms, i have a 1991 honda civic dx, basically i am having a very rough idle, it has a symptom or surging, unfortunately i do not have a tach so i can say for sure the specific rpm that it is idling at however it seems to me to be completely indiscriminate when it occurs, it can occur right at start up or after driving for 20 minutes. my main symptoms are

- rough idling if my foot is not on the gas it will idle very rough and surge. i can prevent this by keeping my foot on the gas at lights( idle surging, lets say if a smooth idle is at 1000 rpm then my car is surging between 600-1050, bare in mind i do not have a tach)

- if i am coming up to a set of lights without my foot on the gas the car will resume the idle surging and while sitting at the lights i have to pull my e brake and hold my foot on the gas to prevent it from stalling

- at certain random times the car will stall out completely ( i can prevent it by stomping my foot on the gas to bring it out of the stall) and about 50% of the time it will not start again, it will crank but will not turn over. if i leave it sit for a couple minutes ( or sit there and crank for the same period of time becasue it stalled in the middle of the road) it will eventually start with no warning.

What ive done to the vehicle
distributor
cap and rotor
plugs(no wires)
air filter
fuel filter

I have a couple technician buddies who by spraying i believe fuel straight into the injector, bypassing the hose from the air filter, it would start briefly while it was in the period where it wouldn't normally start leading them to believe it was not a spark issue but a fuel issue.

I have no idea, nor do my technition freinds and i am wondering if you guys might have any ideas what it could be, any help would be greatly appreciated

edit- forgot to add that while driving a couple days ago a check engine light came on which it has never done before, however when i turned the car off and back on it was gone

 

I've been having the same issue and there are a number of things that can cause this to happen. Taking the parts you replaces in consideration that leaves you with faulty plug wires, fuel injectors, throttle positioning sensor (TPS), idle air control valve (IACV), fast idle thermal valve (FITV), manifold absolute pressure sensor, timing, vacuum leak or to much air, mass air flow sensor, ect...

Perhaps adjust the throttle cable with a 12mm wrench as it may be to loose/tight.

Check the TPS, which regulates fuel depending on the position of your throttle plate, and is located on the intake manifold on the opposite side of the throttle. Unplug the 3 pin connector and turn on the engine. If it improves idle it could be a bad sensor.

Part 1 -How to Test the TPS (Honda 1.5L, 1.6L)

To test for a bad fuel injector remove the metal clips to the injector plugs and with the engine on unplug one for each cylinder (Just one at a time). If your idle does not change with one of them unplugged you found the faulty injector.

Part 1 -How to Test the Fuel Injectors (Honda 1.5L, 1.6L)

I'd also suggest cleaning your throttle body with some Sea Foam Deep Creep or other throttle body cleaner to remove carbon buildup.



Hope you find this information helpful.