Zac2003

ok so I have 160k miles on my car and it has a vortech s-trim

well the other day I went from 50-150 on an empty long stretch and then it started running like junk.

I start it and the throttle is quite responsive @ first when cold

after I drive for 5 mins or so and its warm it cuts out and all kinds of stuff almost dies at stop signs and sounds really crappy through the exhuast when i get on it.

a blown headgaskets wouldnt make it run like this would it? its running cool as usually so I don't know whats up.

btw.. I changed the plugs today to ngk tr6's and its still doing it grrrr.

optispark? I changed it like a year ago but ive since had water on top of where it sets when i had overheating issues, but it just did it all of a sudden the other day when no water was near it!

thx in advance!!

david97gsxr

i don't know for SURE. but i've heard the o2 sensors don't start working until it's up to temp. soooooooo, maybe after 160,000 miles they went out and once it's warmed up the a/f ratio gets out of whack

Zac2003

well, they were just replaced 2,300 miles ago, thats how many miles i've put on it since the blower install.

so maybe alcohol injection is messing them up or what?

david97gsxr

i don't know, i'm not educated on that kinda stuff. if i were you i'd do a search on o2 sensor failure symptoms. and what makes them go out.
i've heard that seafoam and stuff like that screws your o2 sensors. so chemicals could mess em up.

maybe someone more educated will chime in

Zac2003

well i'm not sure because I had'nt drove it to terribliy far you know? and hav'nt used seafoam.

anyhow maybe someone else knows if its the opti or what

bluezed28

The OS sensor is a possibility. When the car is cold the O2 sensors are not active so the computer runs in an open loop. Meaning its runs without most electronics that affect emissions and drivability.

There are 4 O2 sensors on the car, two before and two after the cats. the two before the the ones that make a difference on driveability. Are you sure those the ones that were replaced.

Also, I would check your plug wires to make sure none are burned out.

wile2k

Some further information would be helpful, most namely the year of the car.

If it runs normally when cold started and only exhibits the symptoms after warming up then I'd assume that it is related to it going to closed loop. Is it running totally normal when cold? Or is it just running better cold but not normal?

Very hard to diagnose imo without getting some data. Do you have any other Fbody friend around that do their own tuning or scanning?

If you can get some data logged (datamaster for instance) I think the problem with readily present itself (messed up O2 sensor etc.).

Also, is it throwing any codes?

Zac2003

95z28 and are you sure there are 4 02's? I only saw 1 on each side of the exhuast when changing plugs last nite.

damn i just bought these when it was in the shop how much are they ?

p.s. yea when its cold I dont really go all out but it runs pretty much like normal when cold so .....

stang_killa94

you should have changed the plugs and wires. Cause thats EXACTLY what happend to my car about a year ago. I changed the plugs and wires and it was good as new. About 2 months ago the same exact thing started happening again so now i gotta swap the plugs and wires again It'll run nice until the car warms up then down the Sh!tter it goes. And the more you drive it the worse it'll get. My car is resting in my garage becuase it got to the point where the car doenst even have to warm up. As soon as i turn it on it does it.

96 Z28 CBR900RR

The first thing I'd do is check your codes. Mine was throwing a code P0372 when doing almost the exact same thing. Called the dealer and they said it was my crank position sensor. It turned out it was my camshaft position sensor was just unplugged. I suppose they told me crank sensor because it's more likely to go out. Anyway, see if there's any codes present in that computer.

wile2k

Ok, well, 95 is OBD1 and only has 2 O2 sensors and no crank position sensor (just to clarify).

If it comes down to it you can check with Dal or Jason Cromer (search for their info) on O2 sensor prices. They will be better than your local dealer most likely.

Really need to be able to scan it and get some data to accurately figure out what is going wrong. I'd be thinking a screwed up o2 sensor or burnt o2 sensor harness (maybe even an exhaust leak before the o2 sensors) might be causing the problem. Really hard to isolate without some data though (well short of throwing money at parts that could be causing the problem, but that isnt usually a good idea).

Sorry I can't be more help.

stang_killa94

i dont wanna sound like i know what im talking about becuase i really dont but your problem sounds so much like mine and my solution was changing those plug wires.

Zac2003

well I do have an exhaust leak Ive had it for a while on the manifold gasket but it hasnt made it run like this before haha it ran fine now total junk lol.

how can i check and see if the 02 is bad?

djk19

I have the same problem with my car. I had just replaced the wires but I know one of them came close to my headers. I think it might have messed it up. I haven't figured out what the problem is yet but now I can try the o2 sensors and get the trouble cods and knwo what to look for. thanks guys! I will post amessege when I figure it out!

Zac2003

I'm going to try and fix mine tomorrow so i'll be sure and post up to if I figure out whats up with it.