92 Civic Rough Idle

civic

#1

Hello People.

I have a 92 Civic CX that im having an odd issue with.

The car runs fine on cold start, with RPMs showing ~900-1100 as per standard honda norm. An important tidbit is that the idle issues are affected by the weather.

In 30-60 Degree weather, the car runs fine. No issues. Strong pulls. Nothing out of the ordinary.
In 20 Degree weather or below, the car revs itself up and down by up to 800 RPM. As this has a IACV and FITV, i attribute that to the FITV and have adjusted it since.

But, the fun part is that if it is 72 degrees and above, the car does the following:
Starts fine. Car warms up and thermostart gets up to temperature. Car is still running fine at this point.

~10 minutes after it is warmed up, at any stop light, stopsign, or any reason to be stopped. The car feels like it has a skipping cylinder.

Normal Idle is 750-850 RPM.
When it does this, it drops down to 550 RPM, then raises back up to 700 PM while still feeling rough.

What i have done so far:
New NGK plugs, new OEM Honda Distributor Cap and Rotor, and new NGK plug wires. - This was done as I couldnt recall when this was last done.

Still having the same issue.

So any thoughts on this are appreciated.


#2

Figured it out. When i did the timing belt, it was the dead of winter and we didnt double check it. So it was 5 or 7 degrees retarded on timing… Thankfully a stupid easy fix.