I have Pacesetter LTs, and an ORY with some 3" exhaust (not sure which one) There are O2 sims for the rear sensors. Car runs a bit rich, poor gas mileage, SES codes (through my Car PC scan tool) showed 0300 random misfires, or sometimes cyl 6 misfire. Also shows O2 sensor issues for rears, so they were not deleted, makes me pretty sure it was not tuned after headers swap. It also pops after revving above 3500 or so.

The other night it rained hard while we were out, and it started ******* and missing. part-to-WOT seemed to get it to run, but then it would start missing again. A couple of days later, still missing. We haven't driven it in the rain before (had the car for a month now). I read a post that said the AIR check valves can cause some of that, and then another that said pull the O2 sensor plugs and put dielectric grease in them, that they dry out and get water in them.

I've now pulled the AIR system, plugged the vacuum, pulled one o2 connector and greased it, other side looked high and dry (they used an extension cable with plugs on one side, and spliced cable on the other side and taped up that side well. I then changed the plug wires, put in Belden premium wires, fixed a cracked pcv hose...

Fired it up... grrr. Same thing. cleared and read codes, cyl 6 misfire. So I think I might move the coil pack and see if it changes to another cyl. I think cyl 6 is one of the tough ones to get to on the pass side?

Anyone have any other ideas on troubleshooting this? Open to suggestions. I'm going to try to get some o2 sensors soon, maybe that's all it is.

Oh and I did clean the MAF very carefully a while back, no noticeable difference. Car was not missing like this before the rain, but the rain was last Thursday.

 

Well I swapped #6 coil pack for #2, made sure all was plugged in well, cleaned the MAF wires, and started it up. Sounded good at first, then started missing after a couple of minutes. Tried to check to see which cyl was showing misfires, and as luck would have it, my OBDII scantool was not showing up on the computer any more. So I'll have to look tomorrow, once I find out why it's not working right.

all very frustrating... At least I managed to get all the wires changed out, and I'm getting where I'm feeling comfortable messing with this engine. It's bigger and newer than any I've worked with before.

 

my buddy had a weird miss fire back on his old motor it turned out to be a bad valve seat.... and it turned out to be the doom of his whole motor. but you'd prob hear a ticking if that were case...

have you checked the plug on #6? its always possible to have one that took a **** on ya..

 

similar thing happened to me.......my car still has not cleared up......and i am clueless

 

what happens to your car cuz my car has been acting miss firey but it was after i did some obx headers, but i put the stock manifolds back on and it still dose it... it just pops and the car jerks at wot and around 3/4 throttle.. its also guttles as hell! but it throws no miss fire codes.. or any other at all except EGR and AIR, that was deleted...
its been like this sense May and im dying to fix the problem

 

after rain i lost an 02 sensor try that sounds like the same thing as what mine was doing worth a shot

 

I bought some new o2 sensors online, we'll see if that helps anything. Maybe I'll just do some engine detailing and stuff in the meantime. The car is no fun to drive at the moment...

 

best of luck man!

 

Sounds like some new 02 sensors would work wonders for the car. I ran into the same problem back in the day when I ran my car through some water. New 02 sensors fixed it right up. The misfire might still need to be addressed but I think it will clear up a lot of the issues.

 

milburnr, did the O2 sensers work? mine did the exact same thing last week, update please

 

Update:

I swapped coil packs #6 <-> #2, and got the scan tool working again with the help of ObdPros support. Cyl #6 misfire, still. SO... it's not the coil pack. Time to (gulp) change those plugs. Mind you, my hands hurt already....

Ok so 1, 2, 5, and 7 were easy. 2, not so bad. 4 was terrible to get to - took about an hour before I figured out the right combination of extensions and wrench. Previous plugs were NGK TR55G-something. Then I pulled #6. holy cow. gap was about .060, and I was very careful pulling it out. And it was an AC Delco. Considering that when I changed the spark plugs I found one boot was barely touching the plug, the oil dipstick bracket bolt was loose about 1/4", the header bolt above plug #4 still had an 11mm socket on it, and a 15mm bolt above #6 was backed out about 3/8".... I'm not too surprised at the #6 plug.

So I put new NGK TR5 V power plugs back in. All I have is LTs, oh and I have braided brake lines I discovered - cool huh? -anyway so I think until I swap cams I should be ok without the TR55 or higher temp plugs.

I got it back together, cleared the trouble codes, started her up, and it sounded much better. I let it warm up, backed it down the drive, and as I got to the main street, it started bogging down.

Well as we were driving, we had the OBD_DIAG tool reading PIDs, and noticed some interesting numbers on the O2 sensors (keep in mind we have 2 sims instead of rear sensors):

Bank 1 Sensor 1 - seemed to fluctuate normally, got up to .900 or so.
Bank 1 Sensor 2 - stayed around .445-.450
Bank 2 Sensor 1 - stayed at a constant 1.105
Bank 2 Sensor 2 - fluctuated a little, around .445 I think.

So... looks to me like passenger side o2 sensor is toast. Good thing I have two of them on the way now, UPS ground. I'll update again when I get them installed...

 

Hey there's a guy who has some used o2s if you need them, I was going to get them but ended up getting new ones online, thought he had sold them already. very good deal, his ID here is mikedamageinc. He has a post in classifieds.

This is just speculation, maybe someone can verify... but it would explain my issue and also jb98camaro's issue too... I had a cyl 6 plug that likely wasn't firing. So prob that means unburnt fuel was hitting the sensor. Also I don't think the car was tuned after putting long-tube headers and off-road Y + new exhaust. From some reading last night, it sounds like that kind of thing can foul your o2 sensors. Also I was reading that they have internal sensors to detect O2 in the exhaust flow, and external (outside the pipes) to detect atmosphere O2 levels. If that gets wet, maybe it can mess them up? I dunno, seems it would be so hot that water could not affect it, and they are so close to the ground... although I think on mine they are much farther back than stock, hence closer to the ground than intended?? Anyway, I am pretty certain that the reading on my B2S1 sensor of constant 1.105v indicates it's toast. I think it is telling the engine to inject more fuel... if I understood what I was reading? There's a diagnostic manual which indicated values are 10 - 1000mv where higher numbers indicate more fuel needed. If so, then 1105 is off the charts and it's dumping gas like crazy. Explains the heavy gas smell it's giving off now. Also explains why it's missing so bad.

Up to about 3500-4000 rpm it's ******* badly, then it will surge and run normal. I think that's where it is no longer closed loop (i.e. O2 involved in fuel calculations), which also makes me pretty certain it's the sensors.

 

let's hope you say that fixed it cause i have the exact same problem... and i drove through a massive puddle about 2 months ago....big...

 

Up to about 3500-4000 rpm it's ******* badly, then it will surge and run normal. I think that's where it is no longer closed loop (i.e. O2 involved in fuel calculations), which also makes me pretty certain it's the sensors.[/QUOTE]

Same thing my GTO was doing. I also ordered new O2 sensers and while I'm at it added 42 lb. injectors, sending the PCM off in the morning to get tuned and we'll see what it does then. Definitely keep us updated Milburnr. Weird how it happened but as soon as I get my stuff back I'll let you know . Subscribed

 

Check out this thread:
https://ls1tech.com/forums/new-ls1-o...r-run-bad.html
yeah that's exactly what mine feels like. I don't quite understand the rain connection, but it was doing this mildly when I first got the car, I thought it had some kind of power control circuit where if you gave it a little gas it played nice, but a lot of gas it would suddenly surge. Actually kinda like Dodge Chargers do under normal operation... (push gas, wait for it, wait for it, ummph there it is...)

 

yet another...
https://ls1tech.com/forums/new-ls1-o...dies-idle.html

 

Alright Milburnr, I thought I would experiment a little before I put in the bigger injectors. I did add new plugs and went to O'Reillys and bought 2 new front O2 sensers, installed them and the goat sat there and idled like a brand new car, except louder. Thats been 2 days ago and its still doing fine. So I guess next week I will install the injectors and I'm going to order a new fuel rail. I hope this fixes yours too. Nothing like a good rain storm huh? Good luck and keep us updated..

 

OK. I got the new sensors. I bought ones without plugs, for I have a perfecly good set of plugs already. I wired them in, hooked them up, installed the new sensors (btw one old sensor had a lot of soot buildup).

Went and started it and it's running much smoother! Not 100%... but we looked at the codes and the PIDs for the engine, and it seems that Bank 2 Sensor 1 is not giving a signal. Or at least the signal is not being read. It is sitting at .435-.450v for that sensor, while bank 1 sensor 1 varies from .030 to .950. So there must be a wiring issue, which I will trace down tomorrow somehow. I do have a multimeter after all

In any case, it's not running very rich at all, and it's driving pretty good. Doesn't seem to be missing.

 

In any case, it's not running very rich at all, and it's driving pretty good. Doesn't seem to be missing.[/QUOTE]

Good, glad it is better. Did you put both sensors in or just the one?

 

Good, glad it is better. Did you put both sensors in or just the one?[/QUOTE]

I put both sensors in. However... when checking the wires for the passenger-side sensor, I inadvertantly mashed the metal pieces inside the connector (doh!). When the sensor wasn't registering, I removed and and found the problem. I found (hope this isn't a plug) the connector parts at Napa, no other local auto parts have them. Once I fixed the plug, and reinstalled the sensor, it was responding normally... and the problem seems resolved.

I did cut about 12" out of the extension wire, it only needed to be about 18" and it was much longer than that. I don't know if that mattered at all.

I haven't tried to get the car wet, and rain is not in the forecast. But hopefully this fixed the problem. I sealed the wires up tight with electrical tape.