i have a 87 z28 with a carbed 305. when i got the car everything was fine, exept after about 1 hour of driving, it would just die. And once the engine cooled down, it would start up again. i dont have a licence so i dont know if that problem still exists(ive put new igniton on). Well after putting new igniton on, it idled really weird, so i(my dad) drove it to the shop and the we started it for the guy, and it ideled like crap, then randomly idled fine, as if the choke was going on and off. So its been sitting for like 50 days now, and i rolled it outa the drive way(open headers so its really loud to start it in the garage), and started it outside, started fine, and idled OK, very low idle, like 300rpm, and then it would idle up high, and then go down again and just about die. then when i hit the gas, it sounded and felt good, but when i hit the gas the second time, it shook and definitly sound like it was missfiring, so i shut her down. Back to the day i took it to the shop: the mechanic checked the firing order, and he said it was good, buuuuut, i had to the wires off to put the headers on, and i lost the sheet, that had my firing order written on it, so i looked online, and did accordingly to what they had set on there. and now it randomly misses and stuff, THEN, i found the sheet that had my old firing order!! and its differnet!!, so the firing order that i went to the mechaic shop set with, that they said was right, is differnt then the online chevy small block firing order!


ok, if u read that... THANKS, and if you can reply with ANY HELP, then THANKS X2

 

Ok i fixed it... im embarresed to say... the problem was a loose spark plug wire... lol.

Im very happy though, it runs lika beat now. I just wish that open headers were legal.

But if the problem where it dies after about an hour of driving still exists, what could i do to fix that?

 

What type of fuel delivery system do you have, pump etc.? And what all did you replace in the ignition, coil too? Also make sure your choke is opening fully when the engine is hot.

 

I dont know what kind of fuel delivery, arnt most fuel pumped?

And for the ignition, i did new wires, plugs, rotor, and cap. And that lil moduel thing inside, and some little springs and 2 peices of metal.

 

Do you have a mechanical, block mounted fuel pump? I've had one go bad before, only after getting hot, and then it made the engine run like crap. I've even had the same thing happen with a faulty coil after getting hot.
And those "2 pieces of metal" you replaced inside the distributor are the centrifugal advance weights. Unless you know how to tune a distributor well, messing with the weights and springs can cause more runnability problems than you thought you were fixing.

 

OK i thought that the loose plug wire was the problem, but they are really really hard to get onto the spark plugs tightly. But when i started my car today to take it to the muffler shop to get the exhaust welded up, as soon as i started it, and hit the gas, it was very shaky, i was sooo happy last night when i thought i fixed it.. but no, it randomly runs good, then randomly runs bad lol.

I'm going to complety re route and redo the dist. and wires tomorrow, and hope it was maybe just arching through the lead wire, going into some other part of metal on the car.

 

I have the same car with the same motor and the same problem. I have a block mounted fuel pump, too and a rochester carb that I'm having rebuilt right now. I put another carb on the car and it fired up and ran amazingly so I hope thats all thats wrong with it.

 

ya, im just not sure if my problems the carb, cuz sometimes( like today it ran amazing all day when i went to pick it up at the muffler shop), but then sometimes.. its crap... lol soooo confusing.

Goodluck with ur car though.

 

And i have this fuel pump, and its brand new.


http://www.classiccarauto.com/impala...p_location.jpg

 

Yeah, my fuel pump is mechanical, too. I bought a rebuild kit for my q-jet today so once I get that done and slap it back on there it should run fine. If it doesn't I'll start looking into other possibilities like the fuel pump. I really want to convert it to tbi but I don't have the parts I need yet.