so my 91 max with 234,000 on it is misfiring occationally and its driving me nuts. I ohmed out some injectors last year and one was out of spec so I figure thats it.

So anyway now getting around to considering changing injectors so I decide to test them all again to make sure that is what the problem is, but first I put some new ngk plugs in for grins. then i go get food

Now the car is missing non stop so I figure -good I can figure out which cylinder is causing the problem.

after doing the pull plug wire and listen for difference i find my cylinder. Then i start to ohm out all the injectors. two are out of spec and I cant get to the one under the manifold. (one that was out of spec was the cylinder that was misfiring). well I plug everything back and now the misfire has gone from one cylider to two other cyliders and the first cylinder that was missing is now firing. (I determined this by the pull the plug wire and listen for the difference method) wtf batman I hooked everything back up?

anyone have any ideas? sorry for long post. ask me more questions if I wasnt clear enough. btw I dont think it is spark as I put in new plugs and can arc from the end of the plug wire to ground with no problem or skip in the beat so to speak.

 

idea:
when you removed the connector for the injector, you may not have put it back on properly, or it went on weird, or something.

a bad injector can "come back to life" sometimes (in fact, it seems that is what they do; they work most of the time, and stop for a little bit, until it just gives up the ghost).

 

im pretty sure the plugs only go on one way plus i blasted them with contact cleaner so they shoulda been better than before. the cylinders that are missing now both had injectors that tested within tolerance

 

hmmm...
you may wanna try wiggling the connectors, to see if it gets better or not, if you haven't tried it. if it helps, the inside of the connector may need to be bent a little on the inside, to make better contact on the pins of the injector.

 

did it already

 

It's not a far fetched notion that 2 injectors fail within days of each other, i've had 2 fail within a month of each other..

It might be a good idea if you just replace them all..

 

right but the two that are misfiring now tested good about 1 minute prior to me firing the engine. Anyone ever have injectors not work that ohmed out good?

 

i had 3 fail in a week. heck, you drove my car 4 weeks ago and it was running strong then.

 

Our injectors usually start to fail intermittently,(i.e...good one second...bad the next....then good again)...Then they progressively get worse over time, staying off for longer periods of time, and the frequencies of the failures also increase, until total failure occurs.

Be sure you do not have corrosion on the injector prongs, this will make your ohm tests,"not so accurate" so to speak..

 

well I went back out today and now only one cylinder was misfiring so I unplugged the injector plug and blasted it again with some contact cleaner and did the same for the plug then I bent the prongs again on the injector in hopes of better contact and it is now firing on all cylinders.

most of the time anyway. It still misses like a ****

 

sounds like injector replacement time big guy..