I had a B16 put in my car a year ago after my turbo D16 went out. The car has been running perfect until about 3weeks ago it started to stumble, the tach and engine would fluctuate wildly about + or -, a few hundred rpms. It finally died while I was driving down a bumpy road and wasn't getting spark, it ended up being the ignition coil. It still has the same problem though as if something is loose, before I put together that it was only stumbling when the car wasn't on perfectly smooth pavement, I changed the plugs, wires, cap rotor, fuel filter and some of the questionable vacuum lines. I reset the ecm, checked all the fuses, jiggled everything sensor I could think of to see if it was loose. Does anyone have any ideas on what I could check next?
Thanks

 

I had the same problem...

Check ALL of your engine grounds... One of mine under the hood was loose and caused a hell of alot of problems...

Have someone else start the car at night and watch for sparks under the hood...

 

I replaced the one up top on the valve cover, gonna check the others tonight or tommorow.

BTW, Where are and how many grounds are there? I know the valve cover to body one, the tranny to body one off hand, too dark to really get a good look right now.

 

Mine was located somewhere beneath the main set of electrical plugs, that are mounted on the side of the engine compartment, beneath the battery...

It's kinda hard to explain... My bro noticed it when I tried to start the car...
Sparks could be seen... Can you have someone watch while you start it or vice versa?

Actually there are a bunch of them... Look at all your connections... It drove me crazy for 2 months before we found out it was a loose ground...

 

Been a few days, but christmas time gets hectic. I went to check my starter ground and cannot locate it, should it be viewable from the top of the engine or do I have to put it on ramps?

Editing this post, I see a 10mm screw hole on the starter and I assume that is where the ground should be but nothing is there, I ran a piece of wire from it to the negative battery's ground point (there sharing it) The car seems to run much better over smooth pavement but still acts up when I hit bumps, sometimes when I jump on the throttle in top gear, and around some corners. I have a grounding kit from ebay ordered last week which should arrive this week, hopefully.

 

I think I may have solved it, I changed the engine grounds and tightened up my tranny mounts which were wayy too loose. It still has the problem but only very very minor. I think the tranny mount may be bad or anyonther mount may be on it's way out, I guess the shock over that bumpy road combined with the loose tranny mount must have made the ignition coil blow. I swear it's always something, well, ....silly. Thanks again