i have a 93 civic with a d16z6 was rebuilt 90000 miles ago it revs up and down around 900 and 1300 only at idle and sometimes it will act normal and somestimes it will die but takes a secound to die when it dies it will idle down to about 100 or 200 i have replaced 3 map sensor a throttle body with tps sensor distributor cap rotor button and a coil pack. sometimes i can smell gas as well

 

Does it drive OK, just not idle consistently? If so, dirt in the IACV is a very common cause. Also check the valve clearance. This is all assuming there are no ECU codes set.

 

it shows map sensor and a iat sensor how do i bleed the coolant system after clean theres no bleeder on the thermostat houseing

 

and how do i check the valve clearence

 

ya it dirves fine sometimes how do i check valve clearance

 

I'm having the xact same problem, 92 Civic DX 5speed...I was also told it was IACV issues...I was guna buy a new one but if there's a way to clean it, id like to give that a try 1st.

 

i tried to clean it but didnt do anything is there a certain way to clean it i just ran through and srayed it with air

 

Resolve all codes before expecting the car to run properly. Is the plug with a solid white wire on the MAP sensor? It is possible to swap it with the TPS.

 

Theere right I checked the timing it looks right

 

Check if the MAP and TPS have their 5 volt power supply and ground. There may be a short / open in the wiring or (rarely) faulty ECU. The 5 volts comes from the ECU and should be present whenever the key is on.

The output wire of the TPS should be 0.4 volts with the throttle closed and increase proportionally to about 4.5 volts at wide open (do this test with the key on but engine not running). The MAP output should be about 3.5 volts with the key on not running. When running, the voltage will drop due to manifold vacuum being developed.