I'm having this problem with my Civic. Its a Ej8 with a y8. For some reason my idle it varying between 1,200rpms and 2,000rpms but not a constant thing, just every now and then. Today the check engine light came on and when I push the gas soft it goes to about 1,800rpm and gives me like a rev limiter type of thing. Its hard to explain... i think its a sensor (of course) but i was just wondering if anyone knew what sensor can do that? tps? knock?

 

Start by retrieving the CEL code:

https://honda-tech.com/zerothread/1901557