2f/aisin running real rough.... help....

[RBHME]

So new rebuild on carb, 3 months ago. ran great. so yesterday was driving and noticed it getting a little rough. would accelerate when pushed but would not cruise or maintain speed. decided it was time to get back home. on my way it got rougher and rougher. Almost did not make it back from the corner to my house as it really was rough and a quick back fire. it will idle and runs strong like it normally does under hard acceleration. So I changed the fuel filter this morning thinking what the hell. So it ran great, went intown and as it got warmer it ran worse and worse. Not as bad as yesterday but it is drier and warmer than yesterday. As it gets warmer it runs worse. So it is between 2k and 3 k rpm that it is the worst. I am completly confused what is up. any ideas?

RBHME

 

[IDave]

Is your heatriser stuck in the closed position?

 

[RBHME]

when i did the weber to aisin reconversion i used the MAF heat thing not the stock heat riser. I do not remeber seeing a plate....... does not mean there was not one.......

 

[Ian Rogers]

you mean a fluid heat riser. do you have headers

 

[IDave]

Yup. Headers? Besides the heatriser, which may or may not be an issue depending, you may want to look for a vacuum leak that progresses with temperature. Time for a vacuum gauge?

 

[RBHME]

ah, sorry, yes on fluid heat riser and yes to headers. actually have the ceramic headers.
I was thinking about vacuum.... looks like I will have to do a vacuum check....... AAAHHHH!!!!

 

[IDave]

No biggie. It is one of the most useful diagnostic tools you can have!

 

[72FJ40]

i would replace or clean your pcv valve, i recently experienced very rough running and that was the culprit.