I have a small problem with my 1990 RX-7
When cruising, if I let off the gass just a tiny bit, the car bucks, and feels like I just touched the brakes.
If I just give it a TINY bit of gas to start speeding up or to maintain speed, it gives another really bad jerk, and always backfires. It feels like I am hitting the gas really hard for a split second, then letting off.
I have adjusted the TPS a gagillion times using the 1volt, 1ohm and lites method, all without succcess, what is it???
Also, the car seems to be running rich. My mileage is CRAP and the pipes have black carbon in them. I also get a hesetation, or cough if I hit the gas hard while at at 2500 rpms or lower. Any way to adjust the mixture??
BTW- the engine was just rebuilt because an apex seal got carbonned up, and I had the problems before the engine rebuild (carbon, again, from running rich I'm sure)
ANY help would be great!!!
Dan

 

Has the engine been properly broken in yet???


-Ted

 

i also have the same problem after i installed a TII engine into my car, yes broken in..

 

The engine now has 3000 K on it, It's broken in, and I had the rough idle transition problem before I put the new short block in. Is it the TPS? What is the most accurate method to adjust it?
Is there a way to test the TPS to see if it is bad?

Anyone have a clue about the hesitation problem at low RPMs??

 

the bucking and the crappy mileage might be 2 different things - i had the same problem with the crappy mileage, turned out to be the oxygen sensor going bad then when it finally crapped out i got the error code. had carbon on my pipes too.

does the bucking feel like when you don't properly warm up the engine and try to go high rpms? i still need to research why it does it on mine when i don't warm it up like 3 mins before i drive it.

 

This sounds alot like my problem. My car bucks also, is bitchy with the gas, and backfires. I wasnt really watching the RPMs though, I noticed it happening around 4psi.