Thread: Random smoke and power loss.

I just picked up a 98 grand prix gt.

Here's the problem. It will randomly just start smoking like crazy and fall on its butt. I scanned it for codes and i get misfire on cylinder one, lean code, and coverter lockup.. I changed the oil, put a new fuel filter on it, and changed the plugs. Number 1 plug was the only one that looked bad. Car ran great till about 5 min from my house and it started up smoking again. This time it gives me Random misfire, lean code, along with the coverter lockup.

So today i check the fuel pressure regulator and its fine. So i figure i will check it again when it starts smoking again. Well i drive all around and now it won't do it again. I still get the lean codes and later on i got a coverter lockup code again.

The owners before me cut the cat out of it and welded in straight pipe. I also know there is a slight exhaust leak at the resignator. So im thinking that might be were my lean codes are coming from?

So if anybody has any ideas what is causing any of this let me know.

the smoke is more of a blue color like oil or sometimes fuel. No, im sure they didn't delete the codes for the o2 sensors.

My initial guesses were that the number 1 injector was dead/dieing, fuel regulator was acting up, or a temp sensor.

OT: But whats the best way to go about deleting codes like o2 and whatnot. Ording an ECM like off ebay with what you want or is there easier/ better way. Whats the advantages to this/ disadvatages to this?

Typically lean codes are from vacume leaks on our cars. But that is just from my experience.The code for the cat is not going to cause any issues from it being on. But the right way to do it would be to get it deleated. Sometimes the ses light does not come on even when the cat is deleated. Sometimes it comes on after driving for a while. Sometimes none at all. So that may be the issue for the code not being there at the time you checked.

Refering to UR Losen's Comment: The o2 sensor is there. These people just cut the cat out and welded a pipe between were it was. Im sure it would still give a code of some sort.

Does it only do it going down the road, or at idle? Blue smoke rules out coolant, so it's either oil or fuel....and if it's running like poo, it sounds like fuel. So you must have a bad misfire on that one cylinder that came up. Check your wires, the boot connections on the plugs, and look at the terminal on the coil pack for that cylinder.

Alright i think i might have figured it out!! Explains everything I think. I started it up and was listening to the motor and i noticed some hissing sounds, 2 to be exact. The 180* vacuum tube fitting was cracked underneather it. It actually broke into three pieces as i was trying to take it off.

So there was a nice big vacuum leak that i was able to fix for .99
I put that on and i notice there is another hissing sound. I finally find it and its at the dipstick. The dipstick tube had a decent amount of vacuum. So Im guessing that my pcv valve is sticking, which would explain oil burnoff/loss. Im thinking/hoping that fixing these two things should fix everything else.

I let it idle for awhile after just fixing that vacuum line and plugging up the dipstick tube and I never gave me one code. Usually it would give me a lean code. So TDCRacing was right about the vacuum leak.

Im going to check the pcv valve tomorrow and hopefully take it for another test drive.

Vacuum on the dipstick would lead to a pcv valve being bad. I think you've got it licked now!

Awesome! Thank me with the thanks button!!! Glad you got it fixed.

Not sure if i don't have enough post to use that option yet or not or something because i don't see any buttons for that.

You can purchase an "O-2 Emulator" module for $45 at ZZP. I recommend also wrapping the downpipe with header wrap due to the heat sensitivity of the emulator. The emulator plugs in where the rear O2 sensor was plugged in. You can remove the O2 sensor and plug the hole with an oil drain plug from Auto Zone. Bring the O2 sensor in to match tne theads. I've had mine on for about a year now with no problems. The emulator tells the PCM that all is well between the two O2 sensors which translates to "your cat is doing its job". This may be easier or cheaper than a code removal.
TMC