99 z28 bogging badly

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06-15-2008, 08:26 AM
snadoramac4

99 z28 bogging badly

i dont know what is going on with my z28 but it has been bogging really badly. seems like worst when shifting form first to second. its an automatic and seems like it just falls on it face. it also seems like when im on the fuel and accelerating that it will pause and then regain power then pause again but i know i am not moving my foot at all. i want to fix this because i know that this thing can preform way better than it is right now. its a 1999 z28 stock its my daily driver and im looking to get it sold by the end of the summer but i want the next buyer to be happy with what it can offer and i want to fix it before trying to sell.... let me know if anyone else is having problems or if you have any ideas.
06-15-2008, 09:12 AM
joker_01z28

MAybe a clogged fuel filter, my 89 firebird did the same thing, i got a new filter and it helped alot, the old one looked like it had choco milk coming out of it.
06-15-2008, 06:15 PM
9t8z28

Mileage? We need more info? Any SES light?
06-16-2008, 07:37 AM
snadoramac4

just about to turn 85000. no lights no warnings just started happing out of the blue. i maintenance it all the time, as i work on a race car so im always on top of that stuff.
06-16-2008, 07:40 AM
tigersport14

get a new air filter and buy some fuel injector cleaner. it could also be clogged cats, along with the dirty fuel injectors. so if you have time try to get the cats checked out
06-16-2008, 08:22 AM
cant.b.caught.z28

its most likely fuel related. My z28 had the same problem. I replaced the fuel filter, it solved the problem, but then about 2 weeks later my fuel pump went out. I'm in the process of putting a new walbro pump in.
06-16-2008, 08:24 AM
tigersport14

why did your water pump go out?
06-16-2008, 08:35 AM
cant.b.caught.z28

fuel pump
06-16-2008, 08:42 AM
tigersport14

:sillyme: feul pump*
06-16-2008, 08:58 AM
cant.b.caught.z28

I miss my baby, I haven't been able to drive it for the last month because I don't have enough time ever to work on putting the new pump in.
06-16-2008, 09:17 PM
camarojunky74

you need to get a scanner hooked up with live data, such as a tech 2 or even your buddy's diablo sport,

what you are looking for is a high fuel pulse and a lean a/f mixture under wide open accel if this is the case you are looking at a new pump and or filter, probably both. i would start their it seems as if your gonna need a pump.

also under accel, does it shake when it has a lack of power or just doesnt go?
06-17-2008, 04:41 AM
konigandy6

hahaha, junky, I just have to say NICE avater!!! F'in Richard Simmons.
06-17-2008, 07:04 AM
snadoramac4

it doesn't seem to shake when it looses power just doesn't go. although sometimes i notice a little shake when i'm at idle at a stop. i just noticed that i need to see how consistent that is. i figured it may be the cats being plugged up but haven't had a chance to get under it yet. thanks for all the suggestions i will try all these and let you know the results let me know if there are any more>
06-17-2008, 10:14 AM
konigandy6

Quote:

Originally Posted by snadoramac4

it doesn't seem to shake when it looses power just doesn't go. although sometimes i notice a little shake when i'm at idle at a stop. i just noticed that i need to see how consistent that is. i figured it may be the cats being plugged up but haven't had a chance to get under it yet. thanks for all the suggestions i will try all these and let you know the results let me know if there are any more>

Cut the cats off and replace it with a good exhaust setup. LS1's are notorious for plugged cats (I have seen many warranty claims on them since they carry a 8 year 80k mile warranty)
06-25-2008, 05:32 PM
cant.b.caught.z28

Did you get it figured out?
06-26-2008, 06:47 PM
niterunnr

what do u suggest for cat replacements... i was told headers heat up the fuel lines causing the gasoline to boil in the fuel lines and vapor lock......cause the headers are so close to where the fuel line comes up through the shock tower area..... thanks i am lookin at headers for my 01 z car....
06-27-2008, 02:38 AM
konigandy6

Quote:

Originally Posted by niterunnr

what do u suggest for cat replacements... i was told headers heat up the fuel lines causing the gasoline to boil in the fuel lines and vapor lock......cause the headers are so close to where the fuel line comes up through the shock tower area..... thanks i am lookin at headers for my 01 z car....

Whoever told you that was hitting the crack pipe a little too hard then...
06-27-2008, 03:16 AM
Too Fast

Nobody has suggested a possible quick, easy fix: Get some MAF cleaner, you could have a dirty sensor (did you oil your K&N or similar air filter). That would skew the readings and not tell the PCM correct airflow (not as much as reality). And yeah, low fuel pressure/clogged catalytics will do the same as well. If it shakes as it is bogging, I would look for an ignition problem first.