Connor280ZX

haven't personally checked the vaccum with a gauge, but I did send the car in to get the vaccum tested and system inspected and according to the guy who worked on it, everything checks out fine.

Replaced plugs with NGK when I bought the car 6 months prior and gapped at 043

Thanks for the input! Thats really interesting. I always thought that when an alternator was going bad, it would overcharge the battery, or start seizing up... What could have caused this? Its a pretty new one after all...

So today i made a trip to a relatives house in my 82 ZX, going through a tunnel, straight shot, and all of the sudden all of my dash lights come on, and my voltage drops to 12-13 volts on the meter. Car is still running 4th gear 40-45mph. after 10-15 seconds, the dash lights go off, but the volt meter still reads low, like the Alternator isnt charging. A minute or so after the Dash lights go off, the Volt meter reads normal (14-15 volts). Throughout the rest of the trip this happens randomly, sometimes the dash lights just flicker for a second when the volts drop, sometimes they dont flicker on at all when the volts drop. Checked all connections that i could, and they all seem tight and secure. Alternator was replaced 10k miles ago by previous owner. No belt slipping when volts drop. Could there be a short somewhere? Bad ground? All input is appreciated.

Follow up post: During the process of elimination, i replaced the Air Control Regulator, or IACV, and now the car runs great! The old on seemed to be partially clogged with black soot, and wasnt operating properly. The misfire has stopped, and the rough idle has stopped as well. Runs so much better!

The ignition was timed about a month ago. It was 10 degrees over advanced, but after the tune it didn't really seem to help. While the car was running I sprayed a bit of WD40 around the gaskets to see if the idle would change, but all of the gaskets seemed to be fine. I haven't checked fuel pressure, but backfiring trough the intake means its running too lean right?

No, i havent thought of that... Do the connectors get corroded?

I thought i was in the clear after i replaced the O2 sensor, and cleaned the AFM, but i was wrong... However, the car did perform great for a few days, then the dreaded misfire came back. It acctually started to backfire through the intake, and at certain times the engine would cut out and it felt and sounded like it was temporarily running on 3 or 4 cylinders. This only happened occasionally, and once i rev it for 5 seconds or so, the car starts to run normal, and i am able to get the car home. Just about 30 mins ago, i replaced the CHTS thinking that this has got to be it since it was totally coated in corrosion and white crusty stuff. I hooked the new one in, started it up and i was dissapointed to see that the car was running just about the same. However, the idle started slowly surging between 900 and 1300 RPM, and would occasionally drop to 500 but wouldnt stall. So pretty much running the same as far as i can tell, havent taken it for a test drive yet. in the past month, the problem has just been getting worse, and i fear that the thing's gonna die somewhere, so i havent really been driving it except for quick runs into town. Heres some specs on my car: 62,600 Miles, 5 speed, N/A Upgrades: PS20 Ignition Coil, MSA Catback exhaust. Parts replaced in past 4 months: Spark Plugs, Plug Wires, Distributor Cap & Rotor, Air Filter, Fuel FIlter, Fuel hoses, Master and slave cylinder, O2 Sensor, CHTS, and the PCV valve. The only other things that i could imagine that could be causing the problem is the AFM, Air Regulator, and the EGR Valve... Or am i wrong?

I've been having this annoying misfire with my car for a few months now. I first noticed the misfire when i installed a performance catback exhaust system in the car. Its not like a loud bang or pop, but its like a bubbly/boiling sort of sounding misfire. During idle, it runs fairly smooth, misses slightly, and surges up and down between 700-850rpm. When i accelerate the engine misfires as the tach climbs. When decelerating, a /rumbling/popping sound occurs. Pretty much the only time i notice the engine NOT misfiring is when accelerating hard. Heres the work ive done already to try and fix this: Replaced o2 sensor, Cleaned AFM, Replaced Master Vac lines, replaced PCV valve, and retimed the ignition. Heres other engine work ive done to my car since i bought it: Replaced Spak Plugs and Plug Wires, Distributor Cap and Rotor, Fuel filter, Fuel Hoses, and the Air Filter. BTW Car is in need of valve adjustment. Car Specs: 1982 280ZX N/A 62,781 Miles. Car was found sitting in a garage unused since 2005 by second owner. EVERYTHING on the car was original down to the Tranny Fluid. Mods/Upgrades: K&N Air Filter (Stock Intake), Crane PS20 Ignition Coil, and MSA Catback Exhaust with Summit Racing Muffler.

Update: I went ahead and bought a new o2 sensor, installed it, and now 90% of the misfire has gone away . As far as the other 10% goes, i think it will completely go away once i adjust the valves. I found out that my EGR valve has a very slight leak, so i will be replacing that soon as well.

That's a very good idea to check the plugs. As far as I know, the o2 sensor is original. That will be the next step I'm going to take to try and resolve this issue.

Thanks for the replies. Checked the manifold/exhaust gasket and it seems fine, however i forgot to mention that my car is in need of a valve adjustment. Im not sure if clackity valves would cause it to be misfiring. The year of my car is 1982, its naturally aspirated, and has 62,538 miles. The only upgrades are an MSA Catback exhaust with a Summit Racing muffler, and a Crane PS20 ignition coil. *Update* I just started up the car after returning home and i was shocked at what i saw. The second i fired it up, it started to idle very rough, and low around 300-500 rpm. After about 5-10 seconds, the car died, but the fuel pump continued to run for a few seconds. I started it up again and it ran just fine for some reason. I actually happened to be making a video of the car at the same time. Please see the video attached. http://www.youtube.com/watch?v=LG19nULM8OA

For about a few weeks or so, ive been dealing with this odd misfire problem with my car. When its warmed up, it misfires under slight acceleration, idle, and deceleration. The odd thing is that once the engine rpms rise above 2300-2500 or so, the misfire dissapears. I just replaced the PCV valve, and got the ignition timed. Cap, rotor, plugs plug wires and fuel filter have all been replaced a few months prior. I went through most of the vaccum lines, and they all seem in good shape. No cracking or splitting. Any ideas on what might be causing the problem?

I have recently installed a Crane PS20 high performance ignition coil purchased from thezstore.com. I immediatley notice after installation that the car is starting to misfire at idle, or under light accelleration. The car however does not hesitate at all. On the packaging of the coil, it says that the spark will be transfered much quicker to the spark plugs over the stock coil. Could this be advancing the ignition timing too much? Distributor cap, rotor, sparkplugs, and wires were replaced only a few months prior.

Yeah, it turned out to be two vaccum lines that were split at the MasterVac. Cut the split ends off, and hooked it all up, now it works great. Thanks for the help guys!

Yes, it is the Auto Climate Control model. Took apart the dash and noticed that there seems to be one large duct that goes to the vents in the front of the dash. It looks like that there are some kind of air direction flaps that control which way the air flows. They are pointing down, directing all air flow to the lower vents. According to the Haynes repair manual these are the "Air-Mix Door" and the "Ventilation Door" as well as the "Bypass Door". BTW, the car currently only has 62,000 original miles, and has been garaged since it was sold.

For whatever reason, no matter what setting i have set the climate control to, air only blows through the lower vents below the dash. Air does not come out of the vents on the top of the dash, or out of the front of the dash. Any ideas on what the problem might be? Also, it has been this way ever since i purchased my car. Thanks.