I have 94 Infiniti q45 that ive Had reliability issues with for the whole year I’ve owned it. It’s always had an issue of randomly getting stuck at an rpm. Recently I can’t get it to stay on. It’ll start and rumble right under 500rpms and shut off. If I give it gas it won’t do anything just stays on at that low rpms and shuts off as soon as I let off. I’ve replaced fuel injector, spark plugs, fuel lines, fuel pump, fuel relay, fuel filter, upgraded the ignition coils to the Ones off vhperformance, it running okay after replacing a bunch of vacuum lines and fuel lines and the lower and upper intake gaskets, after it would just idle super rough and shake at stops. The only thing I didn’t replace was the injector seals bcus i couldn’t find where to buy them at; they were a bit shredded. But later on once I drove it home I sprayed the maf sensor connecter with maf cleaner and it started not wanting to start and and last time I got it to rev up it shot a flame while dying down from 7k. Plz help I bought this thing to daily and having been having issues with it for a while now, one main thing I’venever been able to fix the the issue of it getting stuck at a certain rpm

to NICO! When you say "injector seals" do you mean o-rings on the injectors themselves, or the rubber seals that fit into the top of the intake runners that seal the fuel rail to the runners?

Heath is right about ruling out intake (air/vacuum) leaks and fuel leaks from the injectors. But, swinging for the fences based on a lack of hard data from your troubleshooting.....I'd suspect the MAF connector, they are known for contact issues. Note that it *may* be on the MAF side of the connector (the pins). When it's (just) the MAF connector, it will run great when proper contact is being made, and then run like crap with no warning as the contact becomes intermittent. you could try gently wiggling while it is running rough. you may get a code 12 from the MAF, but then again you may not.
also, if you have the VH perf coils, then you also have a different than stock sub-harness for the ECU-->coil pax. How do you know the firing order is correct?
See a post I made about 1 yr ago regarding smart coil conversion on the VH45DE.

I appreciate the info! And damn you seem to know what you’re doing I’ve gotten the maf code before so I’ll definitely try that once I get back home this weekend

Have you checked your FPCU? Ground out the fuel pump at the FPCU harness, using a alligator clip and wire. See if it runs better