2000 Chevy 3500 5.7L wont go past 1500 RPM

[ProStreetCamaro]

Weak fuel pump and or clogged spider injectors (poppet valves. To check the fuel pressure hook a fuel gauge up to the port on the fuel line up by the intake. Then turn key to on position but don't start the engine. Pressure should read 58 to 64 psi. If less than that you have a weak pump which these trucks are famous for.

Updated spider with multi tec injectors to resolve this problem. This was actually a recall in cali because of the $hitty fuel there was causing all kinds of these poppet valve spiders to fail and clog up.

 

[DieselTech]

Just replaced a Cat today on a 2000 F150 with a P0300 random misfire code......Problem solved.

 

[Thomas1190]

Thanks for the info guys. The spider injectors thing is interesting. I wasn't totally sure the type of fuel setup i had, good to know. I drove my truck for about 15 miles the other day to get the codes back. Got the engine light to come on/blink. The only code i got was the P0300, it went from pending to an actual DTC. I have a hard time beleiving that my fuel pump is gone just b/c of the fact i just replaced the [censored] thing and spent a pretty penny on it too. It didn't have many hours on it before the problem occured. I guess i cancheck the cap and rotor too to see if its loose. But remember the truck idles great, its only when i give it gas it runs like [censored]. So i would think stuff like that wouldn't matter(plugs, plug wires, cap & rotor etc) b/c of the smooth idle. Im 19 and no mechanic so bear with me LOL. I want to get it fixed im just scared it will cost an arm and a leg. Why do parts for GM vehicles have to be sooo expensive!? Ugh i can't get my Ford pickup soon enough lol.

 

[wapacz]

really? I never though they where that expensive.

 

[swalve]

Originally Posted By: genynnc
No way it's a cat... the truck would still run fine at any RPM, (especially an OBDII engine)it just might run rich.


Respectfully disagree. If a cat is clogged, the engine can't breathe and won't go past a certain RPM (CFM, actually). It could physically move faster, like if you were engine braking, but as soon as you opened the throttle, it would act like a jake brake. And probably blow a gasket or the exhaust off.

If the cat is not clogged, but not working either, and just passing exhaust unchanged, the car will run exactly how it is going to run. The cat has nothing to do with mixture management. The upstream O2 sensor manages the mixture.

For the guy with the truck- will it run up higher than 1500 in neutral? If it does, it points to a fuel or spark issue. If it doesn't, then it points to a clogged exhaust. Doesn't have to be a clogged cat, could be a rotted muffler or a crushed pipe somewhere.

 

[Thomas1190]

Hey guys i believe i have found the problem

. So i was talking to my dad and he just said lets start over and go over the basics. Now, i ignored looking at the the cap, rotor, plug wires etc. in the beginning b/c its new and i assumed that couldn't possibibly be the problem. So starting over i took off the air box to get a clear view of everything and i noticed imediately the #6 cylinder plug wire wasnt even plugged into the cap. Next i removed the cap and noticed one screw was missing off the rotor cuasing it to flop around during the high RPM. Found the screw just sitting below. So my question is now, i have some medium strength lock tite, is it ok to use that on the two rotor screws?

 

[Thomas1190]

Problem solved everybody. How that screw came loose on the rotor is beyond me. Now i just got to get it back in good driving condition since its been sitting for over a year and a half. Thanks everyone for the replies, really appreciate it. Man i love this site!

 

[Big_Ed]

The screw was probably just not tightened as much as it should have been when it was installed. Good thing it was nothing serious. The 5.7's are really good engines.