Dave WM

wow, guess I better up my insurance again. My 75 is as nice as this one (the green 76 that is) and I KNOW I have little rust. that's the thing that gets me, unless you personally inspect it how can you bid this kind of money on a car that is known to be rust prone. IF I ever loose my z, I think I would look into an early Mustang, unless the sheet metal support for Z's go up it just seem too big a gamble if you have to pay large sums. I would be to afraid to drive it. While I don't consider a mustang type car to be anywhere near as nice as a Z you cant deny the support makes them a nice classic to own. Hopefully the after market will take notice and make body parts a bit more available for Z's. Perhaps its just a numbers game, lot more mustangs were built and owned here so guess the demand is higher. My fav is the fast back 66, really like the looks of that car, and is one I would consider if I did not have access to a nice Z.

sometimes I get too deep into analysis. Step back, messing with the cap makes it run great, try a new cap and rotor...if that does not fix it then you can get deep into analysis (compression check/fuel/Ign).

hmm well 6 look suspect for sure, the rest seem rich. this is where the color tune would come in handy, you can see if its sparking and evaluate the burn. I would move that #6 injector to another cylinder, get a new set of plugs, and see if the problem follows that injector. Also I noted your are running a plug I don't recognize. generally speaking NGK standard plugs are run with great success on L motors. If moving the injector has no effect then clearly there is a spark issue going on. did you try lifting the plug cap off a bit so there is a spark gap between the plug and the boot? just get it off a tiny bit and see if there is any change in idle. oh and do a compression test to rule out that as a problem, check all cylinders and look for even pressure. Right now I am kinda ignoring the "runs better with cap lifted". I don't doubt you its just something that does not have a clear connection yet. looking for compression, fuel, ignition even on all for now.

so after all the above it runs fine but for hot idle, which can be fixed by lifting the cap, is that right?

here I demo the color tune. now I am not saying this is the issue you have just something to consider if you have a misfire.

Now you got me fired up to look into my own rougher when warmed up engine at idle, cooler weather makes me more likely to wrench on it and see if I can find my problem.

a small brush like used for cleaning paint guns and some contact cleaner from the auto store, followed up with some deoxit will help.

warming up rough idle, things that come to mind is a leaner air fuel mix, which is harder to ignite. I presume you only have this roughness at idle? A leaner mix is more taxing on the ignition system, IIRC fsm calls for .035, but not sure of that. Any weakness in the ign will show up in the leaner idle mix. I have the same issue, idle cold is great get it fully warmed up and the idle is not as smooth. I don't worry about it since its fine at any thing other than idle, guess I could/should look into it. I did try new plug wires and cap recently, no change. Have some new plugs coming. It maybe something as simple as adjusting the idle bypass on the AFM for a slightly richer mix (for my car that is). IIRC I have noted this on a swap I did with a spare AFM (better idle vacuum). You can also see if you have a poor injector, maybe one is flowing a bit less, again a relative power test can isolate this, unplugging one injector at a time and listen for rpm or drop in vacuum is a easy way to find the loafing cylinder. Check it for compression, put a new plug and wire, if still loafing you can try a color tune plug and do a comparative flame color to a good cylinder. if its lean swap an injector and see If the laziness follows that injector. The color tune plug is expensive but a nice tool to add to your diagnostics tricks.

that cap looks a bit beat up from the rotor, maybe that is normal. may as well put some spacers in there and run it with the cap up since that solves the problem. Looks like some alum dust sprinkled around, maybe enough to provide a ground path same as a carbon track? Have you looked at the new plugs since you put them in? Next time this happens you could try pulling the spark plug wire off a little bit and seen if any one plug is effected. I am sticking with the partial fouled plug until you look at them. New plugs can foul if there is a problem.

an old trick I used to use on dirt bikes that were run on two stroke oil (and tended to slightly foul plugs from the burned oil). Sometimes I would have a rough running engine, or even an engine that would not start. I would pull the plug cap off and replace but not seat on the plug, but rather space it off (estimate about 1/8 inch). With that it would start and run fine, at least long enough to get back to the pit area. Not sure of the science of why this worked, but work it did. Pull the plugs and take a look at them, see if partial fouled. better yet just replace them with some new ones see if the issue goes away.

the ones I got are working great, I would NOT use the skillard, I want something that looks like factory, what they have looks like it would work, but does not look right to me.. Call up zcarsource and find out whats up. You want the ones with flocking and correct formed to fit the existing hardware. Its not easy to install since you have to figure out a good way to attach, maybe they were getting too much griping about that and pulled them form the listing.

which is why I posted, no one changes their minds and there are different sides each have members here. Typically I would not post but after having to withdraw from this before I felt like getting my view stated, then leave.

biden has his own problems with china and Ukraine, not to worry he is a trojan horse anyway.

Very nice!

yes all the OE emission controls are intact and functional.

I get it, I suppose it would be hard to be the person that takes that title away. It would be like taking a survivor and putting a sbc and wide body kit on it.

I hear all the reasons not to drive your car, maybe I am getting old, but what heck I would take your 350 mile version and drive it to Alaska!!! You only live once, and money is not everything. If I can get a million miles on mine I will be a happy driving camper.. get yours going and I will meet you at pikes peak.

dip stick readings are done cold, and at the same location, a garage on a level floor. I like to allow time for the oil to drain back from the top of the head.

I am tempted to get in on the action for that green one, sweet!!!

just thought I would note this and see how others are doing I wipe the dip stick, insert then pull out, then wipe the bottom and sides of the dip stick after drawing out to mark on the card. H and L are the top and bottom of the hatch marks, mileage is noted on the bottom. I started above H with a new Nissan filter and 5 Qts of 20w50 VR1. My goal is oil and filter every 3k (or 6 months if that comes 1st) but looks like will be adding 1 Qrt pretty soon. The engine has I think 110k (could be more of course but I suspect this is correct based on overall wear). Plug insulators look fine, I get some black carbon build up on the edges, fairly dry. I have no external oil leaks, no oil in the radiator. I drive very conservatively (2.5k to 3.5k rpm) last check of compression was about 160psi +- 5psi across the board. IIRC the bottom of the hatch marks puts you at 1 quart low. The oil pan slopes so I suspect the readings on the dip stick will be non linear to usage.

smoke the intake, look for leaks

the project farm guy is really great, both informative and entertaining... lets find out...

that's an interesting oil filter cooler, can you tell the diff in the pressure with it on vs off? that is once you get to sustained operating temps? I like the idea of the alum oil pan, just don't like the $$$ for it.

another thing to check, see if the evap line is clear back to the over flow tank. Its the hard line that is routed with the fuel and rear brake lines. Mine was rusted, rendering the evap non functional. Its steel and can have condensate in it, making rust a problem, more so that even fuel lines. If you can blow thru it you should be ok. Its got designed restriction, but still you should be able to blow air thru it. I cut the bottom section out (where the rust was) and used some hard plastic line to replace. It was beyond clearing with cleaners and air, solid rust internally. If you opt to replace it with steel, its a pita, lots of bends and have to remove the various lines to get access into the rubber mounts used to route the other lines. I love originality but only if it functions as well. If not I fix it with OE if possible.

have you tried pulling a vacuum? also you will have to replace the drier now (prob got moisture in while disconnected). The drier if its the 33286 style is NLA, so you have a choice, have it rebuilt (can be done, have to cut open and replace desicant) or bend up the hard lines to fit one that is close but not exact fit. R-12 can be had and would be the way to go. having pressure in it means good chance the internals will be ok. Pulling the vacuum and seeing how it holds will tell a lot. The OE compressor is very sturdy, I have the OE in my 75 and it works just fine. You should check the small filter on the firewall high side, its under the fitting, just make sure its clear (do this while the system is not pressurized).