hi there, have a problem with my 1993 rx7 efini. on a 100 mile drive back to my home and after about 70 miles the car started to splutter. my fuel gauge has been sticking recently so i thought i may be running out of petrol so i filled it up but the problem continued. after about 15mins of this i went to overtake a lorry. i was doing about 3500rpm and when i put my foot down there was no throttle response and the engine stayed at 3500rpm. i then took my foot off the throttle completely and it still stayed at 3500rpm as if i had cruise control! i then decided to turn the engine off whilst coasting along, but when i took the key out, the engine continued to run at 3500rpm!!
it then ran ok for a while but after 5 minutes it started spluttering again. i came into a 50mph zone so dropped the eninge into 4th gear. when the revs dropped whilst i had the clutch in it didn't idle jus completely cut out. at the same time, all the electrics stopped working so i just rolled to a stop. once the car had stopped the electrics started to work again but the car didn't start.
Any ideas would be appreciated. Thanks

 

also the starter motor seems to be turning over fine but the engine isn't starting. i've had the engine rebuilt 1500 miles ago so an engine rebuild wont be the problem. cheers

 

Sounds like you have a fairly nice electical issue going on there. Start with the battery and alt. and work your wayback. That stuff is time consuming

 

I can't think of the reasoning for the dieseling effect but the 3500rpm could be a sticky throttle linkage/stuck cable and or a stuck/open injector...

 

You have to becareful when you remove the key while coasting. Your steering wheel will lock and before you know it you are wrapped around a tree.

 

i had a similar problem to this but luckily i wasnt at or near freway speeds or anything. i was driving and after a quick acceleration i let off but the car did not, so i put it in neutral, turned the car off and then tried to restart it but it did not restart. hmm...stepped on the gas as if it were carburated(used to own a 69 camaro, only way to start it, lol) and it fired right up...what the hell? pulled over, everything seemed normal. limped it home, let it sit, looked at it next day, didnt start, tried the gas pedal again, started but 5000 idle on a cold motor...AHH!!!! turned it off, then it clicked in my noggin. tps was loose, thats what it was for me. i didnt have your electrical woes though.

good luck