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Ok so here is then run down.
I have a 93 nissan sentra 1.6l ga16de with a manual 5 speed transmission 222,000 miles and just cannot figure out what is causing
The engine to misfire every time the car is taken out of gear and is at idle some times I can even hear a misfire between gears
So I started by changed the plugs with ngks, changed the plug wires, changed the air filter, changed the idle air control valve, checked for vacuum leaks using carb cleaner, changed the belts, cleaned the MAF, changed the distributor, did a power balance test all 4 cylinders are firing and decided to change the o2 sensor, the car seems to really miss when the car is out of gear and the brakes are pressed, also there is no check engine light on so I’m running out of ideas looking for a little help.
Thanks guys
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How did you do a power balance test? If it’s missing at idle you should have been able to pinpoint the cylinder that’s misfiring.
That said…I would do a compression test next.
I pulled the injector wires and with each of them the engine shuttered and normal revs returned when the injector was reconnected
The car usually will idle around 650 with each injector the drop was Down around the 500rpm mark, typically when the car does miss then it will go from 650 down around the 550 mark before coming back up I’ll try a compression test and get back with the results
So you have spark at the wires right? you could have an injector on its way out. had it happen to me. basically it will be an intermittent issue. U might end up with the random misfire code. could this be and idle issue that you are mistaking as a misfire?
I changed the fuel filter no change, picked up a compression tester and i will post the results later, is there any way to tell if a injector is going bad or figure out which one it is because there is no check engine light
Looks good to me. At least you ruled out a low compression cylider. I’ll keep banging my head for you.
The only way to properly check and injector is with an oscilliscope. You can also check injectors with a fuel pressure drop test.
Check this out http://www.youtube.com/watch?v=SsYMi3yl0T4&list=PL8D535FDBDA971307
Isolate the power brake booster by removing and plugging the vacuum line to it and road test. You could have a weak diaphragm in the booster that is causing a momentary vacuum leak between gears of when the brake pedal is applied.
To tell you the truth if the injector is going bad it will manifest its self with a check engine light in a few weeks. for me it was a week and a half. Good compression. So we are dealing with a spark or fuel issue. Did you get spark at the wires? at the plugs? I don’t see that you answer this question yet.
Ok so I went out today and pulled the brake booster line and plugged it and it mad a big difference but there was still a slight miss
So maybe there is a really small vacuum leak somewhere else, now I tried using carb cleaner and couldn’t find anything does anybody have a different suggestion, and how difficult is it to change the brake booster
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