Bad Idle, bucking, unstable rpm
 

Hey everyone, i recently just got the car "finished". Got it as a shell and put in an engine with 30k miles. compression is at least 100 on 3 faces of both rotors. I'm using a JDM harness and did the necessary wiring to get it to fit the USDM F harness. I'm currently running consequential, throttle body coolant eliminated, double throttle gone, AST gone, oem ecu, oem intercooler, and plugs are 9's & 7's. It starts up right away, no problem with that. It idles very poorly very rough. It's like it's searching for an idle. I can hear little "misfires" when i give it a bit of gas to around 1200rpm or so. Another problem is when i hold it at around 3k or so, the rpm would drop back to 2500ish and thenb ack to 3k. It would do this over and over and over. Up down up down. Does this at almost every rpm. No codes, any help would be grateful thanks!

Have you checked the TPS (Throttle Position Sensor) ?

Adjusting it correctly makes a huge difference in driveability?

It completely eliminated the bucking in my FD when I adjusted it.

Search for it here and in the archives. I believe Dale Clark has a good writeup on the procedure.

Links to a few threads on that topic is also in the FAQ stickied in this forum. Read it.

bucking and werid rpm was cost by bad alternator, just got shitty idle now.