tim99ws6

iTrader: (31)

https://ls1tech.com/forums/showthrea...ighlight=13111



i hate to bring up a dead thread and all, but i am getting some what i would call "weird" symptoms.....

The car has driven was driven for i'd say 200 miles on this past friday. It drove great, no problems with surging/stuttering what-so-ever. Then, about 25miles from my house, i was cruising about 1800rpm in 6th gear, and the car started sputtering, almost felt like a carberator car loading up.....I thouhgt it might have been cam surge, and accelerated slightly, and it cleaned it out. Unfortunately, just as soon as it settled back into that cruise range of a constant apply of light throttle, it would start sputtering....

By the time i got to my house, it was to the point i would call it "violent" sputtering. I noticed the car was having problems finding it's idle also. Weirdest part is this:

As soon as i accelerate, the car felt fine, and would accelerate with no bucking i could notice. As soon as i tried to go back to cruise throttle wise(light throttle, just holding current rpms and speed) it would start violently bucking.


Initially,
I thought my 2-step was messing me up. So, i unplugged the 2-step yesterday, and drove for about 30minutes into town to have the codes pulled at Auto-Zone. Codes pulled showed Bank 2 Sensor 1(passenger side 02 bad). I thought "huh...that's weird....if a o2 goes bad, usually it'll throw off the entire rev range, not just idle and cruise charecteristics"

Now to make it weirder: When i took the 30min drive to AZ, i unplugged the 2-step from my coil packs. Now this may just be coincidence, or what not, but when i fired it up, bam, no SES light, and car drove perfectly......Now, after i left AZ, for peace of mind, i plugged back in the 2-step to the coil packs. I made the ENTIRE drive back, just waiting for it to happen. I got to within 100feet of my house, and bam, here comes the stutter...


I drive it past my house, and back out to the street. I confirm the stuttering is still happening, and pull over and unplug the 2-step back off the coil packs(trying to see if the 2-step is at fault).....well, sure enough, that did NOT fix it........it still stuttered like crazy!


So, big cam guys, tell me, when an o2 goes bad, is it similiar to this? I will probably have it scanned this weekend, but i know for sure that at least one o2 is bad, so i'm replacing both already with 13111 o2's. I'll go ahead and pull plugs and see whats going on there as well.


The thing that really concerns me is what Beast posted in the thread i linked to. I have heard a couple guys on this board saying a 2-step has killed their cam position sensor. How can i diagnose the crank, tps, or the cam sensor is fried on my car? I don't understand how it can accelerate fine and seemingly "clear out" like a carb car loading up on fuel.

I am at witts end guys, and appreciate any light you can shed on the matter.


EDIT: i decided it was best to make a new thread, as i just noticed how long-winded this post was, haha. Sorry!

tim99ws6

iTrader: (31)

Little help please!
Thanks

Phil99vette

iTrader: (11)

Tune Tune Tune... My 254/260(346cid solid roller) doesnt stutter @ any RPM. Could be a dirty MAF or a bad tune.

tim99ws6

iTrader: (31)

I really don't think it's tune related, as the car did NOT stutter at low RPM until the end of the 200mile journey. Then it started at low RPM's violently out of no where. it's just really odd. Also, it isn't just low rpm's. Once it starts this violent stuttering, it will do it at any RPM, as long as it's held at that rpm at a constant rate(like driving at 3000rpm for 100yards, and it'll start bucking)


I also seriously doubt it's MAF related, since it starting doing this while the car was running SD. I did plug back up the MAF, but it made no difference on the problem.

Thanks for the idea Phil! I guess i just put the "big" cam part in the title because it's hard to decifre(sp?) cam surge and bucking....but i'm telling you this car stutters violently, as if it were loading up badly.....it's odd....I hope it's just an o2 sensor

Am i going after it in the right direction with this diagnosis?

Phil99vette

iTrader: (11)

Send your file to phillip_eclipse@hotmail.com

tim99ws6

iTrader: (31)

let me get my hands on it.

Why would it jsut out of no where show up like this? i mean the tune has been dead-nutz on up until this happened......

CamTom12

iTrader: (1)

File sent, Phil!

KrisXpc

iTrader: (13)

I had the same problems on old plugs, Tr55's solved it here =]

Hope im pointing you in the right path.

98Z28MASS

iTrader: (6)

yea could be the plugs, also might be a clogged fuel filter or an injector issue, or even a clogged air filter, as it sounds like its getting choked out a low rpms. My guess is that an injector is clogged or not firing correctly or that your fuel filter is clogged and at low rpms its not getting enough fuel to the engine, however when you get on it and drive it at higher rpms the fuel pump is getting sufficient fuel to the engine due to the higher pressure when you accelorate. Id say swap in a new fuel filter (like $5 bucks at autozone) and if that doesnt fix it try to find someone local to swap injectors with.

tim99ws6

iTrader: (31)

Thanks guys. I already swapped injectors and it did not seem to help.

I will be replacing plugs, o2's, and fuel filter this weekend. I doubt my plugs have more than 5000 miles on them, but it's worth a shot. My fuel filter might be about time. I think it's got around 10k miles on it.

Sounds like a tune-up day on the TA. I'll let you guys know how it comes out.


Like i said, the weirdest part is it can drive for an hour and NEVER do it. Then, out of no where, it starts doing it like crazy. Most dumbfounding thing i've ever dealt with. I'm interested in pulling the plugs and seeing what's going on there....

eamador11

check for loose plug wires, or wires touching headers and check O2 sensors.