Looking for some help in trying to narrow down cause of problem encountered after swaping MPFI to my 91 CRX-DX about a month ago.
The car seemed to run great (and very strong) for about a week after completing the swap. Then about three weeks ago, I started noticing that the engine would surge, running very erratically at RPMs above 3K. Engine fluctuates +/- 750 RPM. For what it's worth this seems to be more pronounced in the morning when cold and also seems to be getting worse with time. Car continues to run without a hitch below 3,000 RPM.
Any suggestions as to where to start looking for my problem (Note: When answering, please keep in mind that I'm not a mechanic)? FYI, components from the swap included intake manifold assy, ECU and distributor from a 1990-'91 CRX-Si, a HASport wiring harness and additionally, installation of DC Sports 2-pc header.
Thanks in advance for any help. pws