I have an 89' crx si with an injected d16a6. I rebuilt the engine a few months ago and it has ran great until now. The car runs fine when the engine is completely cold, but as soon as it warms up it sputters like crazy and isn't as powerful. It isn't as bad at higher rpms, but i cant drive around like that.
When I took the spark plugs out i found that all of them are very white meaning that its running lean? Does this sound like a burnt valve?Any input would be helpful, because i really don't want to be forced to put my old crappy cylinder head back on. I'm going to run a compression test soon, ill let you all know what I find.

 

do a leakdown test to find out for sure

 

Do a leakdown test. How are your injectors? Gunk can really effect how a car performs.