low idle miss - ZR-1 Net Registry Forums

1FST ZR-1 · 04-04-2008

Trying to decide on what to change first. Car has 60k on and gets driven like it should, it has a low idle miss that is noticable from the exhaust note.I drove it from Redding ca to LA and back and averaged 28 mpg with a few120mph blast so it seems to be in tune. I had a good backfire a while ago so I thought it may have a vacuum leak under the plenum, so after a quick plenum pull all was well. It has rc injectors and the stock wires and coils. I did notice that when I pulled the #2 plug wire the rpm did not seem to change so I pulled the #1 plug wire and it seemed to do the same,(no change in rpm). But each plug wire was firing after i pulled them off so does that mean the coil pack is ok or can it be weak? I mean other than the very slight low idle miss it pulls just as hard as ever. Anyway I have done a quick fuel pressure check and both pumps are good and the injectors are holding pressure and it always starts hot or cold. So any thing to check plenum on or off? Thanks for any help.

04-04-2008	#1
1FST ZR-1 Join Date: Mar 2008 Location: Redding, Ca Posts: 5	low idle miss Trying to decide on what to change first. Car has 60k on and gets driven like it should, it has a low idle miss that is noticable from the exhaust note.I drove it from Redding ca to LA and back and averaged 28 mpg with a few120mph blast so it seems to be in tune. I had a good backfire a while ago so I thought it may have a vacuum leak under the plenum, so after a quick plenum pull all was well. It has rc injectors and the stock wires and coils. I did notice that when I pulled the #2 plug wire the rpm did not seem to change so I pulled the #1 plug wire and it seemed to do the same,(no change in rpm). But each plug wire was firing after i pulled them off so does that mean the coil pack is ok or can it be weak? I mean other than the very slight low idle miss it pulls just as hard as ever. Anyway I have done a quick fuel pressure check and both pumps are good and the injectors are holding pressure and it always starts hot or cold. So any thing to check plenum on or off? Thanks for any help.