My 92 honda accord ex as a rough idle at stop and if i put in it reverse the idle is alot rougher. it idle at 750rpm

If it's running rough, chances are that it's misfiring. If the Check Engine light is flashing/blinking, it is definitely misfiring.
If that's the case, drive it as little as possible... Or straight to the mechanic because the more you drive it while it's misfiring, the higher the chance is of you ruining your catalytic converter.

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That is normal, in park or neutral there is no resistance on the engine when you put it in gear there is resistance because the car wants to move. Also when you turn on the ac that turns on the compressor that is run off the belts of the engine so it puts more resistance on the engine. Low idle is not a problem unless the engine dies.

If it does that when the engine is warmed up (full operating temp.) it may be you iac valve, or your fast idle valve. They get gummed up. It also could be your PVC valve, but probably not.:


IAC in red. Fast Idle in yellow. Your PVC valve is plugged into the valve cover (the black hose in between the red and yellow in the picture) it simply pulls out. It should rattle when shaken.
Hope this gives you a start on the problem.

if u see check engine light then there is a fault, probably idle solenoid ,wiring , ECU

sticking valves. the short run of the engine free's them enough to enable runnig

D4 is slipping and not engaging. This means you need a transmission. you're losing a gear

you need to FILTER the air coming in the intake with something screen or something zip ty some screen and paper towel .then give it an oil change and clean the plugs(do this first).

Idle may be set too low adjust idle speed

http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c1528005f265

Hi, Here is thi information that you are looking for.

92 Accord with vacuun hose disconnected from the fuel pressure regulator is 40 to 47 Psi. At idle.

With hose connected 30 to 38 Psi. At idle.

I hope this resolve your question.
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