i sold my friend my rx7 a few weeks ago and bought another one(an 85) and now the 80 i sold him wont do 35 miles an hour and it idles at 12 or 1300 when its normally 800. it sounds really bad. we replaced the ditributor cap and rotor and that didnt do it thinkin maybe it was misfiring. could it be a really bad exuast leak? only thing is is that its not that loud. i have no clue. when ur drivin it will backfire constantly. the carb was rebuilt last year. also idk if this has ne thing to do with this but the night all this happend it was smokin from the trans bell housing really bad but the trans is fine???? any ideas

 

i dont know anything so dont take my word for it.
but ide check compression on the rear housing.. does it sound liek a lawn mower. cuz if it does it could be you have a blown rotor..

pull the spark plugs one at a time and listen for the poofs 1 strong 2 bad means apex seal and 2 strong 1 bad means side seal.

 

sounds to me like a vacuum leak.

vac leaks will cause a high idle, and a jump from 800 to 1300 says vacuum leak to me.

if it backfires, it might possibly be a failed shutter valve, if you take the top off your air cleaner, and hear some honking coming from one of the holes, it's probably the shutter valve.

although, don't take my word for it, i'm still a slight noob compared to a lot of other people on this site who have a lot more experience than me. just my suggestions based on what i've read here.

 

See if you have spark on the leading (lower) spark plugs...





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