1998 Civic w/ B16a2

Was driving on the Henday last night, going about 125 km/h when I came up to a hill, halfway up the hill the car started slowing down real bad... 120, 110, 100, 90. Car seems real 'rocky'. Best way to explain the sound is that it sounds like a WRX exhaust. Higher RPM's is less noticeable. Lower RPM and idle sounds like a subie.

It seems to hold idle at 1000rpm's fine, but if you give it gas it will drop to about 500 before it starts to raise.

I can still get up to 140km/h but it's a struggle. I initially thought headgasket but no unusual smoke from the exhaust... (other than the black smoke it normally has from runnin rich)

Also put an oem headgasket an golden eagle headstuds in at the end of summer.
Any ideas?

 

my homie had some messed up valves and his b18 was runnin on 3 cylinders and it sounded like a subaru.... hopefully thats not ur problem tho...

check that all 4 spark plugs are firing?

 

I blew a hole through an exhaust valve about 15,000km's ago... I swap the head with a low km one, new gasket and studs. Would be odd if it happened again.