intermittent cylinder loss

[funky technician]

hay guys, lately my 93 auto has been every now and then loosing the number 3 cylinder, but it is not like turning the cylinder off, it just slowly starts to loose its abilty to fire and starts to gradually cut out and then will pop back and be fine. I have spark and compression and air so its probibly fuel, but what? the pump, vacume regulator, or injector. I should also add that all the plugs look good and the same as each other, and also the 3rd cylinder is a lil weaker then the rest of the cylinders because this lower half of the motor came out of the woods and that set of valves was open so that cylinder had to be honed a lil extra and has a little less compression( i used the same size rings for all 4) so I was thinking that if the fuel pressure was failing across the rail, that cylinder would be the first to fail, while the others with higher compression would be able to maintain combustion. It pisses me off too because it only does it every now and then, but I hate how it chugs and i'm afraid its just gonna stay that way and that will really suck, its very cold out hear now and I need to take this thing on a 5 hour trip (each way) to pick up next years B6 motor for her (applause) not to mention it has to last another 3 frigid months before my other car goes back on the road HELP ME FESTIVA REPAIR FORUM GODS!!!!!!!!!!!!!!!!!!!!!!! :lol:

[festivaWES]

Well if all the other cylinders are firiing fine, i would rull out the regulator and the pump.....start with the injector on number 3.....they have a tendence to crack over time on the end of the plastic cap.....my guess is that it's not getting a proper fuel spray pattern. Or your right you lost compression n cyl3 having to hone it out more to get rid of the "surface rust". Probably a combination of the 2

[packrat427]

When mine started missing over 2 years ago , I replaced plugs and wires , cap and rotor. It still missed , I pulled the rail and took the injectors out and it was plugged with sediment , I took a little brass pick and turned the injector upside down and picked it out , and was careful not to damage the screen in it , then I took some Gumout cleaner and sprayed up inside , while still holding it upside down , to flush out the junk , I did the rest also , but only 1 was plugged to the top of the injector.
I have never had a problem with it since .

[funky technician]

When mine started missing over 2 years ago , I replaced plugs and wires , cap and rotor. It still missed , I pulled the rail and took the injectors out and it was plugged with sediment , I took a little brass pick and turned the injector upside down and picked it out , and was careful not to damage the screen in it , then I took some Gumout cleaner and sprayed up inside , while still holding it upside down , to flush out the junk , I did the rest also , but only 1 was plugged to the top of the injector.
I have never had a problem with it since .

highly usefull information, this will be my next course of action, thanks

[GenevaDirt]

Same as Pack...... my tank was full of crap and the filter on the firewall is pretty rusty so I was afraid to change it. I put an inline filter in mine to solve it. But before I did that my injector plugged a couple of times....made it seem like the cylinder was dead....took it out...and cleaned it.... fires right back up and runs fine. I went probably 4 moths before I figured that out....thought the engine was done....lol.

[Dave G]

How do you know that #3 is the only one missing?

[funky technician]

I managed to catch the engine doing it when parked and started pulling off the plug wires, when I got to the 3rd one the car didn't really change that much, just chuged a little harder, indicating that not only was it that cylinder failing, but that it was partually firing because it actually got only slightly worse when the wire came off, if it wasn't firing at all, there would be no change in the engine when I took off the wire. I'm gonna fire some injector solvent through her tomorrow and see whats up then, if that doesn't work, I have to freeze my rear off workin in -10 celcius to get the injectors off

[Dave G]

If it were me, I'd swap out all the likely electrical items first - plugs, cap, rotor, and maybe try a new (or different) wire on that one cylinder. Things like this are usually electrical, in my experience... Although it does not seem possible, spark plugs do occasionally go bad (espacially the resistor type).

[skeeters_keeper]

swap plugs from say #4 to #3 and see if it still does it on #3, if #3 is still the problem swap wires (there *should* be enugh wire on #3 to reach #4, and put #4 on #3, make sure you swap locations on the disty too...) then you will know if its the plug, wire, or something else.

i'm betting injector cleaner will help but we'll see, at least swapping plugs and stuff is free. good luck.

[funky technician]

ya, no its fuel, the first thing I did when this started was check the plug, then replaced them all with platnium to eliminate the possibility. Not to mention that the wires, cap and rotor were new as of this fall

[packrat427]

Injector cleaner will prolly make it worse , if it is already plugged , it will only loosen the other sediment and plug even more.
I am betting you will find a plugged injector , from what you have found and done so far .

[funky technician]

it hasn't done it now in a couple of days, :shock: , I hate this. I'd almost rather it just broke....like right off........whatever it is, so I can look at it and go, " hay this thing boke off, i'll put a new one on!" LOL (and whatever it was, was only held on with velcro) :lol: