rbgetz

ive searched as much as i can take so here goes the latest version. I installed a set of hooker lts about two months ago and did plugs and wires then. ever since i fired it back up there was a little bit of a rough idle and occasionally problems with backfiring and missing. The first time i drive the car it runs perfect. but if i get it warmed up and drive it say within the next hour it usually has a really choppy idle thatll move from 500 or to a 1000 or so. If the windows are down it smells so rich it almost burns my throat. once i start to actually drive it around the motor tends to shake and feel like its about to tear out the mounts and after a little while it'll shift real hard and accelerate hard. I had the codes pulled last week and came up with a p0100 and a random missfire. since then i've been toyin with it to find a fix. Changed the cap and rotor, tested all the fuses, cleaned the tb with a toothbrush and soap (that was a freakin blast in the sun at 95 degrees) then pulled the codes again. this time it only came back with the p0100 and only had the problem with misfiring and running poor once over a couple days. So today after work i decided to take apart the intake and spray the maf tb and icm with air flow cleaner. I knew it wasnt the plugs or wires but i went back through them and made sure everything was tight. pulled the codes again and this time had a p1361 to go with the p0100. I don't know i have left to try? any suggestions? i wanna start a cam swamp next weekend but id like to have it running right first. Im a broke college kid that needs to try to balance payin for all this so i dont wanna blow money on a part that won't help and be screwed. If it has somethin to do with the pcm i'll get it dyno tuned after the cam swap and can hopefully tune it out.
Its a 96 z28 lt1 with hooker lts, a cat back, cai, shifter and thats about it for now. thanks for the help

SPDEMON

If it hasn't been tuned for the headers its gonna run like crap.

Was it running perfect before the headers?

What type of O2 sensors and/or extensions are you running?

Are you running stock or Aftermarket or no CATS?

If you gapped the plugs right, and didn't criss cross and of the plug wires by accident, then you can rule the ignition out.

So that brings us to the header swap. The only thing that the swap would have done was reposition your O2's, which controls your A/F ratio. Sounds like the PCM is tripping out on you and its running pig rich at times.

Get it tuned.

texas outlaw

i would triple check the wires to make sure you dont have any crossed, and then if you have them right i would change out the plugs agian, because i did the heads awhile back on my car and i put new wires and plugs and when i started it back up for the first time it ran like crap and i couldnt figure it out, but i checked my wires and i had one crossed but it still ran like crap so one of my friends suggested to change out the plugs agian so i did and it ran perfect right after i changed them out, i couldn't believe it because i had just bought them.

BadBirdie

not true. it may not be seeing full power gains from headers without a tune, but its not gonna run like crap.

rbgetz

headers have little to do with the tune. you can run more exhaust but that wouldn't make it run bad. headers arent a big deal to computer. i've got no cats on it but have a simulator plugged into one of the back o2 plugs. sends a signal to the pcm that there is a cat and its working fine. for the o2 sensors in the collectors i spliced in a piece of wiring and soldered it up nice and neat. was thinking that could be a problem since it isn't an actual copper wire like the oe sensors. but haven't shown a code yet for it. so im kinda rulin out the o2s unless it could cause the problem without shooting a code? possible?
i just got home from work and the first time i started it up it ran terrible, which is unusual for the first time, and the ses light came back on after i cleared codes last night. it seemed like the loss in power went away a lot faster tho. no clue why tho. any other ideas?

BTLD_LS1

iTrader: (1)

have u tried the coil? I had a similar issue on my 94 when it would get up to temp and heat soak from the head it would miss like crazy

elis94camaro

Sounds just like when I swapped to longtubes. My o2 sensors messed up and my car was running bad just like you described and all I did was bought some o2 extensions and some o2 sensors and it ran smooth again.Btw the o2 sensors dont always throw a code so if I were you I might look into that.

rbgetz

So I just got back from getting the codes pulled and now I'm even more confused. It didn't come back with the maf code. Instead it was...random misfire. O2 sensor and egr. The egr doesn't surprise me since I just capped the tube and left it on the intake manifold. I think I might go through and try to replace them tomorrow

SPDEMON

Actually, its totally true. If you go from a catted stock system to an off road pipe and longtubes, its gonna run crappy.

On an OBD1 its not that noticeable, but OBD2 its very notciable, especially if you are running a completely stock tune.

And since he did an EGR delete, its gonna run crappy.

Either get it tuned, or get a mail order tune to start, and you can always have him update it when you get the cam.

SPDEMON

Well, since you deleted the EGR, that code is obvious.

The misfire is probably from a lean condition caused by moving the )2's further downstream.

Did you remove the Cats or not?

rbgetz

Yeah the cats are gone but I have an o2 simulator to trick the PCM.

BL96TA

Thats not accurate. Ive had 3 LT1's and many friends with LT1s with exhaust and no tune and no one ever had a problem. Your talking in absolutes, like thats the way every LT1 will run after headers and its not true. Please fact check.

lt1-xjs

Sounds like a cracked plug or burnt wire to me, start it and look under the hood after dark.

BadBirdie

yea dude you dont know what youre talking about. this is my cars set up and it runs far from crappy on stock tune

OP your problem obviously lies somewhere else

SPDEMON

So you are running around on a STOCK tune, with longtubes and no cats, and it runs great, with no issues? Good for you!

Either way, he needs to get it tuned, so he might as well take the car to get it tuned and the shop will be able to figure out what the misfire issue is right away, before the OP keeps throwing money at it.

Just my opinion though, but apparently I don't know what I'm talking about.

rbgetz

maf was on its way out. fixed that and it ran fine. had a tune done just for fun too. tune only really helps with headers at wot or high speeds. dont worry about that too much when i only drive in the city

SPDEMON

Cool man, glad you got it fixed. The tune will also help with gas mileage, driveability, and overall performance. Without the tune you should have been running pretty rich.

shicledgend

Ive had a full exhaust no cats for a year and it was fine up untill now.... i got the same problem... i didnt delete my EGR, so im thinking its that or the PCV valve, and you dnt NEED a tune for an Exhaust and CAI

FSTFBDY

iTrader: (1)

glad ya figured it out. a Tune will help in the power and driveability dep. but deff. wasnt your problem as you figured out.

my 97 in sig is still on stock tune. Im actually waiting and looking for an obd1 pcm so I can just use tuner pro rt like I did on my vert.