I put an si motor in my dx and I put an si computer in and did all the wiring and put a si distributor in. So it idles great, but once you get over about 1500 rpm it starts to buck and when accelerating it does ok under high rpms. I thought it was a vacum leak or the distributor so I replaced the ignitor and coil with another one and zip tied all the vacum lines and it still does it. Any other possible things?

 

what year car????

 

1989 civic

 

does it only do it when you are accelerating hard or any time above 1500 rpm?? have you tried just easing into the throttle and driving throung the gears???

 

yeah i have tried to accelerate easily, when you are trying to hold it at a steady speed or hold it at an rpm and it is anything above 1500 it starts to buck

 

probably a stupid question, but did you make sure to retighten the distributor?

 

fuel system or computer? try making sure your fuel pump is good and your injectors have the proper resistance, the haynes book gives you all the specs. try using someone with the same engine's computer...

 

How many miles are on the motor? Did you inspect the head before putting it on?

 

i have tried 2 different computers and the distributor is tight, i don't think it would be the head or the resistance of the injectors because if they had something wrong with them it wouldn't idle good or be fine under high rpm

 

i just noticed one thing, i dont't know if it has anything to do with my problem but under acceleration the water temp guage drops from reading normal to instantly reading cold