OK I bought a 91 civic hb race car this year with no engine. I bought a ZC engine that came from Japan. the guy i bought the car from said it had a Zc in it last and i know it was for sure. I paid to have the engine installed and it runs fine but (its hittin the rev limiter at 6500)its runnin on a pr4, ive been told its for a integra. Ive read it should be a pm6 or pm7 with higher rev limits. BUT they dont work right and i know there both good cause ive tried them in a friends race car and theres in mine and i have the same problem. The pm6 idles up and down and when i gine it a bit of gas it runs rough and then just goes to full throttle while only a 1/8 to1/4 pedal? The pm7 idles a bit better but when gas is applied it just dies? Any body have any thoughts? as the guy that but the engine in moved out west before i got it to the track. I just bought another pr4 on ebay and the guy put a rev chip in it for 9000 rpm but all it does is do the exact same thing as the pm6:banghead: Ive opened both up and they look the same except for the chip in the new one. the pr4 that dont work says on the side 37820-pr4-a60 431-219467AS code on board in side is U1Y-E 02DO1620-1500-1 the pr4 that works says 37820-pr4-ao1 430-101420AC the board says U1Y-E0 02D01250-1500-0 Now is there a OBDO pr4 and a OBD1 pr4? and i just got the wrong one. if so could i just get the rev chip swaped from one to the other or will i have to get a new chip put in the one thats working. So sorry for the novel but im lost and hope to have it figured out by thursday. Ps. if any body knows of a shop near the toronto area the does swaps please let be know. Thanks.