sluggish

[dramo1]

if it's the injectors pull the plugs and see what color they are they should be a light brown. if they are greyish white they are lean and could cause serious problems. if they are black you are rich. do you have access to a volt meter? if so make another post how to check injectors. i'm not sure so i can't help there because i never had to do this.

when this problem occurs is it high in the rpm range or low. when you say 40-60 mph that could be 1st into 2nd gear but that tells me nothing. is the ses light coming on? could be as simple as a new O2 sensor.

car is not able to get past like 3000 rpms foot to the floor ..new o2 sensor yesterday no help..

 

[bossvette]

try the fuel filter, or better yet have the pressure checked at the fuel rails should be 40-45lbs not sure for a stocker. If you don't have enough pressure it will not run well a clogged fuel filter, bad pump or clogged lines could cause this.

 

[nyernga]

l a clogged fuel filter, bad pump or clogged lines could cause this.

and both are easy enough to change yourself. Just as an FYI, never let the tank stay much below a 1/4 tank. The pump motor uses the fuel as a cooling agent and should always be submerged in fuel. You'll shorten it's life by running low too often.

Len

 

[dramo1]

had the fuel pressure checked yesterday..40lbs..mechanic said that was fine..i took the car today to the vette doctors on long island in new york..they had like 14 vettes out in front c4s 5s and 6s..i guess they should know what they are doing..i hope..he told me if i need new injectors..about 800..is that a fair price..he said i could get my own and he would charge for labor only..summit has some good prices approx 250 for a set of 8..my next question is how many lbs per hour injectors should i buy ie..20 21 24??
car will stay under 300hp..thanks again guys for all the help

 

[MBDiagMan]

It still could be the fuel filter. Even with good fuel pressure at idle, a clogged filter will prevent adequate fuel flow for higher rpm.

It's cheap, easy, quick and needs to be replaced periodically anyway. Put a fuel filter on there and try it before committing $800 for injectors and installation.

Good luck,

 

[dramo1]

just put a new fuel filter last week..the starter went so when i was under looking i told him to change it..this was before these problems started..actually i think it has been sluggish all along just not this bad..i am new to this and had never driven a vette before so i did not have anything to compare it to i just thought it needed more hp..but i bet this prob was there all along it has just gotten worse over the last month since i got it

 

[dramo1]

i was just reading another post and it made me think of something..i had changed my stock prom with a hypertech prom..engine was running too cold so i put the stock one back in..i did all of this without removing battery cable..do i need to undo battery to reset computer on stock prom..could this be the problem..if so did i do damge to anything by doing this

 

[MBDiagMan]

If it's still running I don't think that you damaged anything in the ECM.

Back to the fuel issue. Okay you've changed the filter, that's good. Have you done a fuel pump volume test? If not you should make SURE it is done before incurring the expense of injectors. Low volume could indeed cause the problem you are experiencing. In fact it would some much more likely than injectors.

When I have seen injectors fail, they stick, and it's typically only one or two of them which causes a dead cylinder where there is a stuck injector.

To do a volume test, disconnect the fuel line from the fuel filter outlet and connect a line to the filter and put this line in a jar. Turn on the ignition for fifteen seconds. You should get a minimum of one pint of gas in the container. If not the fuel pump can't keep up.

Good luck,

 

[dramo1]

i saw my mechanic while he was testing the fuel pressure have a hose and a jar with fuel pumping into it..i am guessing thats what he was doing..but i am not sure..man the deeper we go the more like an idiot i feel here..i really have a lot to learn..anybody have a question about a problem in there house im their man but cars i am so damn lost its really starting to **** me off..but i guess in time i will learn

 

[nyernga]

but cars i am so damn lost its really starting to **** me off..but i guess in time i will learn

Patience grasshopper. It could even be the sock filter on the pump itself. The whole assmebly can be removed in about a half hour. It's a little metal screen type filter and is more prone to clogging then the inline filter.

A year from now you'll be answering and not asking questions...

Len

 

[G Winter]

Everything I read here makes me think plugged cat. You removed the precats but that doesn't mean the main cat. isn't plugged. Put the car in neutral and rev the engine to about 2000 rpm and hold the accelerator steady,brace foot against tunnel. If the rpms begin to drop you most likely have and exhaust restriction. Usually the rpm will begin to drop in less than 30 seconds.
Glenn

 

[dramo1]

i was hoping that was it..went to muffler shop this afternoon he checked out main cat..unhooked it said cat is flowing fine

 

[Larry's Yellow Rdstr]

For every suggestion made to you regarding your "problem" you seem to have already had that problem checked, and found that wasn't the culprit. What about leaving the car with a competent mechanic until the problem has been correctly diagnosed and corrected.

 

[dramo1]

that is what i did today brought it to a corvette heavy hitter that just works on vettes ..turns out u guys are right and the jerk muffler guy was wrong..the cat was clogged..he is putting in a new one as i write this..thanks again for all the help..i cant believe a muffler shop could not tell it was clogged..thats all they do is that ..how some places stay in business i never will know

 

[Larry's Yellow Rdstr]

Your car should run like a champion now! Glad to hear it wasn't the trans.
Keep the wave!!

 

[MBDiagMan]

For every suggestion made to you regarding your "problem" you seem to have already had that problem checked, and found that wasn't the culprit. What about leaving the car with a competent mechanic until the problem has been correctly diagnosed and corrected.

Unfortunately the auto repair industry is overflowing with people who are great at changing parts, but don't know the first thing about diagnosis and troubleshooting.

A muffler shop is a place where such a guy can hide pretty easily. There is VERY little diagnosis usually done in a muffler shop. A car comes in with noise, they look around, see the hole and replace the pipe, muffler, etc.

Good luck,

 

[nyernga]

Sounds like clogged cats.........does it get worse when hot?

Len

Ok, what do I win for getting the first correct guess????

Len

 

[bossvette]

that is what i did today brought it to a corvette heavy hitter that just works on vettes ..turns out u guys are right and the jerk muffler guy was wrong..the cat was clogged..he is putting in a new one as i write this..thanks again for all the help..i cant believe a muffler shop could not tell it was clogged..thats all they do is that ..how some places stay in business i never will know

Looks like you found a Mechanic you can stay with. Good Luck with your Vette aren't you getting a little snow now?

 

[dramo1]

a little snow wont stop me now..its running awesome finally..maybe i could put chains on the tires for the snow..lol.. changing the cat did the trick he said the timing was all out of wack too.. it feels like a different car now

thanks again boys

 

[MBDiagMan]

dramo,

I hate to rain on your parade, but I need to point something out.

When a cat is plugged, it is for a reason. If an engine is running correctly, the cat will go hundreds of thousands of miles without plugging. Excessive oil burning or rich fuel mixture is what plugs them. For this reason, now is the time to make sure the engine is not running rich or using oil. That way you won't have to replace the cat again in 5,000 miles.

Good luck,