bighoss77

1996 civic i just bought. the car runs and drives great. right after you crank it up it does some mild skipping or running a little rough, if you rev it up a few times or throw it in drive and take off it runs excellent and does not do again unless you go to start it back up. does not matter how long it is that its turned off and back on. you can shut it off and then crank it right back up and does it. the skipping isnt bad, but its there right after you start the car up. after that it goes away. here are the trouble codes im getting:

P1300 random misfire
P0118 coolant temp sensor
P0420 catalyst system efficiency
P0302 cylinder 2 misfire
P0304 cylinder 4 misfire

anyone have any ideas? i dont think the headgasket is blown. it does not run hot, doesnt seem to loose coolant, spark plugs dont seem wet (they are whitish and not saturated) and runs awesome when driving it... spark plugs and wires do not seem to be very old. any help is appreciated.

grumblemarc

iTrader: (4)

Do a full tuneup first. Was the car maintained?

bighoss77

to be honest i dont know if it was maintained. i bought the car off a guy who used it to travel back and fourth to work. car is bone stock with 232,xxx miles. i have no clue if engine/trans is original. there is no water in the oil, and the coolant is full. it does not smoke from oil or coolant. i can tell the plugs and wires have been replaced within the last few months... not brand new, but not very old at all. i tried swapping the plugs around to see if the misfire would show up on other cylinders, but its still 2 and 4. the dang car runs excellent though... i know on other vehicles a bad coolant temp sensor will cuase a car to run rough, im going to go replace the sensor and see what happens.

Former User

Do a full tune up, reset ECU, and then see what codes return.

bighoss77

im going to install the new coolant temp sensor i bought yesterday, then bleed the coolant system/add coolant and reset and see what happens. ill post back results when light pops back on

Former User

This^ is an illogical order for doing car work. Never assume that any CEL code is meaningful or real unless it repeats. Otherwise, you may do work and replace parts unnecessarily.

motegicivic

I am willing to bet the misfire will be a wire issue, since you just got the car, do a basic tune up, cap, rotor, wires, plugs at least.

The ECT sensor is cheap anyway, esp at an aftermarket store, do these things reset the computer.

The catalyst code could of been from the car misfiring and running poorly, if you let it run like that will destroy the cat, if not already.

bighoss77

well this thing has 2 temp sensors one in the head and one in the thermostat housing that both have the same plug... which one do i replace? also, this car has no antifreeze in it, just straight water... ill have to address that too

motegicivic

The computer will trip the ECT sensor that is the one below the distributor.

bighoss77

okay, kinda figured that out it will only go in that spot. battery is disconnected to reset computer and replaced the ECT sensor so we'll see what happens after a few drive cycles.

Former User

Why post on a technical forum, if you have no intention of learning or taking advice? What you are doing is potentially just a complete waste of time and money. I am closing this thread to make the important statement that replacing parts at random is not a strategy that any respectable member of a technical forum should accept or learn.