lukn4trbl355

iTrader: (2)

whats up everyone...having some ongoing issues with my 01 silverado. ive had a slight missfire for a while, and have been trying to figure wtf is going on with my truck...latley its had a missfire mostly when its cold, but when its warm and you hold the brakes just tight enough to barely lurch the truck forward, sometimes its fine and sometimes it misses. p0300's happen very randomly,and suprisingly not often. ive thrown new o2's on it, new fuel filter, new tr5 plugs gapped at .45, new 10.4 taylor wires, coils checked out all right. so i figured its either injectors or intake gaskets? tomarrow im gonna spray carb n choke cleaner around the runners and see if the idle picks up...when i have a little bit of change ill be buying intake gaskets since id like to have new ones for when the tbss goes on but this problem just wont go away. i also still need to test my fuel pump since i have a feeling its starting to go. whats so strange is sometimes the truck pulls abnormally hard, normal, or sometimes runs like complete dogshit...i just dont get it?

and on top of this, when i was driving back from dyno days tonight...i stood on it to get past some drunk ***, it downshifted back into 2nd and i eased off and it shifted into 3rd...wouldnt go into OD for probably about a minute, tried letting off putting it into neutral, back into drive...didnt work, tried going to 3rd and then into D...once again didnt work. i know the MAF has to also do with trans functions, and also a rough idle/hesitation but it was cleaned not too long ago after i cleaned the K&N? the trans has mabey 20k on it now with some goodies so im hoping its something else thats ******* up and not the trans.

if anyone could help point out something im overlooking, or completely missed please let me know! its driving me INSANE not being able to pinpoint this problem

thanks in advance

T.J.

Gadgetized

iTrader: (9)

Do you have the ability to log data? Is it pulling timing? Do you have a stock converter or aftermarket? Can you give a complete list of the mods please?

lukn4trbl355

iTrader: (2)

no sir unfortunitley i do not, the last time i had it on my buddys ethos scanner it had no knock retard, and did not pull any timing. torque convertor is still stock stall at the moment motor mods are LT headers 1 7/8 primarys 3in coll. and full 3in ORY, 3in intermediate pipe to race muffler and 4in tailpipe over axle 4in CAI, descreened MAF, taylor 10.4 wires, ngk tr5 plugs, coolant bypass for TB, ported and polished TB, egr has been deleted same with after cat o2's. thats all i can think of at the moment but i cant find my writeup and am listing what my half asleep self can remember lol.
AFR's are 12.8 @ WOT according to the uego, ive read the plugs and they look like there burning right where they should be, truck was on a 20% mix of E85 and never ran smoother. truck has been tuned by justin of BBP on a pretty agressive 93 tune. trans functions are 80% TM reduction for around town and 100%TM reduction for haul *** mode. truck is geared with 488s, trans is a 4l60 rebuilt about 20-25k ago with some beefed up internals and also has a transgo HD2 sk set up with 2 spacers for the 2nd gear accum, and full corvette servo assy.

lukn4trbl355

iTrader: (2)

also idk if it matters but today, due to my wonderful cognito tie rod brackets loosening up, i saw the VSS cable somehow got torn...if i remember correctly the VSS doesnt only work for abs but also for transmission functions too right? if so can i have my tuner tune these out?

A Low Dime

iTrader: (13)

If the computer senses misfires, it wont let the converter lock.

lukn4trbl355

iTrader: (2)

its very rare that i get the p0300, but the convertor is always locked...unless the code is on just like how youve described, the trans pretty much stuck itself in 3rd gear and wouldnt shift into OD, its like it locked me out of it. if it was in od with the convertor unlocked, it woulda been a different story. but the whole lockin me out deal, worries me a bit

lukn4trbl355

iTrader: (2)

anybody have any clue whats goin on?

TrickyTransAm

Just out of curiosity...did you check your injectors?

My co-worker has a 2001, and apparently the dealership told him they had a bad run of injectors.

It was doing similar stuff - misfires, etc. and it turned out to be a bad injector.
Should be a 24lb/hr injector.

Whats your fuel pressure?
Any one cylinder misfire more than others?

lukn4trbl355

iTrader: (2)

no sir i have not, but that is def something i suspected,specially now with me rolling onto 130k, i figured the fuel pumps on borrowed time and either that intake gaskets or something else that i may be overlooking is the culprit. as for the missfire, due to my mac scanner, it gives the basic po300 code, it doesnt pinpoint which cyl its coming from, which it did on my cousins jeep? fuel pressure i have not tested due to not having the fuel gauge with shrader valve so ive still got to do that, if i remember it needs to be between 50-60 on the fuel rail correct? worst comes to worst i can get a set of 36lb injectors off my buddy for 65 bucks and get a retune, i just dont wanna throw money at things that im not sure is the problem ya know? and i think i might sell my aem uego for a scan guage...def seems like itd be in my best interest

mcfarlnd

iTrader: (15)

No. Do not "tune out" your VSS. Alot of tables in your tune are VSS based. Including shifting, torque coverter lock-up, etc. etc. the wire needs to be repaired. that could be your issue with the shifting problem you stated before.....

Just a thought but, for your inconsistent misfire, you may have another wire chewed up as well.