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

 

Check your maf the rpms jumping around sounds like a maf sensor problem. I think!?

 

i have the same problem, i think. ihave a 93 ls in my 91 hb. everytime i go over like 3000 rpms, the tach jumps past 8000. i would replace the distributor. thats what im going to do.

 

both of you put new engine grounding wires on before you buy a bunch of new parts and see if it helps.

 

make SURE all the wires in your distibutor are really tight and coil is in real solid. Soudns like you already checked that tho but meh

 

The ground from the valve cover to the body I replaced it, the ground from the tranny to the body looks good and feels tight, I am unable to find the ground to the starter though. Is it under the starter, should I get the car on ramps to see it?

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

 

let me know how the grounding works, im interested

 

Like I said, the problem is still present but has been minimized. I shoulda changed the grounds and tightened up the mount and drove after each one individually. But, I can say the car seems to start quicker with the new ground wires. And if it makes any sense, the electronics seem more responsive over, maybe my imagination. The grounding kit I got I just replaced the stock wires with the after market ones, I'll try tying them together or using the distribution block soon. The kit was around $25 on Ebay, if your wires are questionable it couldn't hurt. BTW I also taped up a few ecm wires that were questionable with electrical tape and that helped the problem even more, since the hesitation it still occurs every now and again(although when it does happen it's much more minor) I'm gonna trace the wires under the hood and look for anything that could be worn.