Sputtering/won't rev past 3500rpm...

[Jayru]

Also, this issue has been mentioned in several other threads. Crap in the tank will hamper the performance of a carbureated car and virtually stop a fuel injected car.

Yes, but the other threads i searched through said nothing about sputtering at 3500rpm. It still does it with a fesh gas can and new line (tried it tonight) so i don't think the tank is the problem. I'll be checking ignition next i guess.

[Bambikiller240]

Where do you think the rust in your filter is coming from? Disneyland?

The stumbling at 3500 rpm could be due to lack of fuel flow to feed the engines requirements beyond 3500 rpm (faster it revs the more fuel it needs, duh) Could be the carbs are tuned really shitty, but the rust you see in the filter isn't going to go away if all you do is change filters and tune carbs. It will continue to grow, continue to flake off, and the problems it causes will continue to grow, until one day your car wil not run at all. If you ignore the rust particles that are trying to tell you something, all you are doing is postponing the repair, and increasing the cost of the repair.

[Jayru]

I'm not trying to ignore the problem. I know the rust is an issue/problem. I don't believe however that it is the cause of my current problem.

I put a clean can of gas with a new hose/filter DIRECTLY into the fuel pump inlet, and i still had the problem. So how is it rust then?

[Jayru]

Just to let everyone know and for the archives, fuel/the gastank had nothing to do with my problem.

Turns out the alternator was on it's way out. That coupled with a weak battery was starving the car/motor of electrical power/spark past the 3500 rpm range. With a new battery/alternator/voltage reg she runs like a champ now.

I drained the gas tank as well and little to no rust came out. I'm going to flush it and change the filter again and see what happens. If the rust returns i'll drop the tank.

Jay

[beandip]

Ok, so my car definatly doesn't have one then (72). Yea, i removed those filters when you mentioned that in my fuel pump thread. They weren't clogged, but i yanked them anyway.

Thanks

Check any way because Your car was wired for one and a PO may have installed one. Just crawl and look , it's just forward of the tank where the fuel senser is and the fuel lines exit and return to the tank. It's a cylinder about 1 1/2 '' in dia.

[Coastieee240z]

FWIW I've got a 72 also and do not have the secondary pump (already checked diagnosing an ignition/fuel issue of my own) it's not stock for that year but as beandip suggested it's not a bad idea to check and see if one was perhaps installed post assembly.