2001 LS V8 runs rough cold, fine when warm

Andrizzle said:
Hey joe, when I take the intake off again (this coming weekend). Can i re use the gasket I just put in? The makeup of the gasket doesn't seem like a one-time-use thing. In fact, I was actually pretty underwhelmed with the gasket. The brand new one I put it seemed to be not much different than the OEM one I removed in regards to degradation.
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Yes, I think they are reasonably reusable. I have reused them without problem so far (as long as they aren't several years old).
Check out the link I posted in the other thread just now.
 
Andrizzle said:
Man I have been chasing the same thing for more than a year now. It only misfires when it is cold, and as soon as it reaches operating temp, misfires are gone. I have become so good at changing plugs and coils, that I can do a full set in about 20-30 minutes. I am about to pull injectors myself and try cleaning those.

Of course this engine has OEM coil and injector prices that make everything a second guess before just replacing.

I am running HEET or whatever through the gas tank now, so far no improvement.

The only codes I can get are P0300 (Random Misfire); P0316 (Misfire on first 1000 Revolutions); P0133 (O2 Circuit Slow Response Bank 1 Sensor 1)

Let me know what you find. We are struggling together, my friend.
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I am having the exact same codes on my 2003 Lincoln ls v6. i have also changed many parts on my Lincoln. Let me know if you ever nail it down and ill do the same.
 
Ok this might seem long and i might be asking a dumb question. I have a 2003 lincoln ls that when it sits overnight and i try and start it it idles rough like its going to stall. Sometimes i can turn it off then start it again and its fine, but it i start to accelerate it hesitates then takes off. I can start it over and over throughout the day and it starts fine after the original chugging and you can smell raw fuel exhaust on the cold start. I have replaced the PVC crankcase sensor O2 sensor. When this happens i do not get a code at all. Plugs have been done, intake manifold gaskets are new. One thing i need to ask thats maybe dumb it has a dual exhaust with them both piping together just before the mufflers. One thing is that one muffler is warm to the touch the other is cooler after driving. The exhaust coming out the pipes are not equal when idling, is there a chance that the one muffler is collapsed and causing the rough start. Should the exhaust pipes be equal?? when i plug the warmer one the exhaust seems to come out of the other pipe. Should these be equal and does the small pipe that connects the 2 just push the exhaust coming from both catalatic converters to one?? The temp of both cat converters is the same the temp drops off just before the muffler like 50 deg. Is this the whole cause of my rough idling on start up Thanks all
 
Yes, exhaust should be about equal. The crossover is there to mix the pulses from the two banks to improve efficiency and sound. The muffler could be clogged, but it's way more likely that the catalytic converter is.
With your other symptoms, I would be suspicious of a leaking (not closing all the way) fuel injector.
 
joegr said:
Yes, exhaust should be about equal. The crossover is there to mix the pulses from the two banks to improve efficiency and sound. The muffler could be clogged, but it's way more likely that the catalytic converter is.
With your other symptoms, I would be suspicious of a leaking (not closing all the way) fuel injector.
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Thank you I’m curious if it’s only when it sits and not everyday consistently (when it’s parked in my garage it seems better) would this still be a leaking injector

thanks
 
Biever said:
Thank you I’m curious if it’s only when it sits and not everyday consistently (when it’s parked in my garage it seems better) would this still be a leaking injector

thanks
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It's possible that sometimes it closes better than other times. It's also possible that this is something else (though I don't really have any idea what).
 
With the difference in exhaust temps just before the muffler, I'm surprised you aren't getting O2 sensor codes.

The rough idle and stumble could also be a weak EGR valve... or intake leak as previously mentioned. Do as andrizzle did... and spray around lightly with a slightly flammable liquid. Spray around EGR valve, both throttle body gaskets, and along the heads where the intake manifold mates to the heads.

First thing I would try is changing the fuel filter and put a bottle of Seafoam fuel system cleaner in the tank. Seems like an injector problem first. Maybe also check fuel pressure.
 
04_Sport_LS said:
With the difference in exhaust temps just before the muffler, I'm surprised you aren't getting O2 sensor codes.

The rough idle and stumble could also be a weak EGR valve... or intake leak as previously mentioned. Do as andrizzle did... and spray around lightly with a slightly flammable liquid. Spray around EGR valve, both throttle body gaskets, and along the heads where the intake manifold mates to the heads.

First thing I would try is changing the fuel filter and put a bottle of Seafoam fuel system cleaner in the tank. Seems like an injector problem first. Maybe also check fuel pressure.
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T
 
The temperature on both cats temps are equal, the pipe after the cats were close in temp but as I got closer to the mufflers the temperature difference was significant and the output in the muffler is lower than in the other. I do get 02sensor codes on bank 2 so would you be thinking Cats or plugged muffler. We did sniff the EGR and other parts but nothing found.
 
I’ll give the fuel filter a change it needs it and try the cleaner tomorrow .
I just don’t get how this happens some times on start up and sometimes not
 
If I don't have it backwards... bank 2 is drivers side... and even with the crossover exhaust most of the flow from that bank would exit the passenger side.

You never mentioned which side was hotter or colder, but I'll assume, (bad idea), bank 2 was running rich... causing the passenger muffler to run cooler... because unburned raw gas was making it to the muffler.... because the converter can't handle all of the excess raw gas.

It's also probable that the drivers side converter is going bad and causing the low exhaust pressure on the one side.

Best way to check for converter restriction is to pull both primary 02 sensors, (before the converters), and check for equal pressure. Restricted one will have higher pressure.

If that checks out, then pull both secondary 02 sensors to check for muffler restriction the same way.
 
Yes
04_Sport_LS said:
If I don't have it backwards... bank 2 is drivers side... and even with the crossover exhaust most of the flow from that bank would exit the passenger side.

You never mentioned which side was hotter or colder, but I'll assume, (bad idea), bank 2 was running rich... causing the passenger muffler to run cooler... because unburned raw gas was making it to the muffler.... because the converter can't handle all of the excess raw gas.

It's also probable that the drivers side converter is going bad and causing the low exhaust pressure on the one side.

Best way to check for converter restriction is to pull both primary 02 sensors, (before the converters), and check for equal pressure. Restricted one will have higher pressure.

If that checks out, then pull both secondary 02 sensors to check for muffler restriction the same way.
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Yes bank 2 is the colder muffler with the code (drivers side ) I’ll do the pressure test in both sides of the cats and see what I get. Glad you mentioned the flow would be more out of the passenger side muffler through the crossover. Thought it was a plugged muffler but hopefully the pressure test will tell me more.
 
So will any flammable spray work like carb cleaner or mass airflow cleaner be ok or do you have an idea what works better
 
When you do the fuel filter... don't forget the Seafoam fuel system cleaner. It's one of the better, (if not best), products on the market. I run a can every 6 months.

(Not affiliated, and no compensation was provided for the above endorsement)
 
So I did the pressure tests on both O2 sensors locations both are even and no signs of back pressure. I did the spray (looked like I washed my engine with MAP cleaner) no changes in idle. Went to change the fuel filter didn’t know I need a special tool for the one end until I tore it apart so abandoned that after trying to get the one end off for an hour. Try again next weekend. Bought Seafoam to put in. Lost on what my next steps are appreciate everyone’s help.
 
Then it may be an injector. Try using a screwdriver as a stethoscope, and listen to all the injectors on bank 2... to see if one sounds odd.

Do this during a cold start, when the car will be duplicating the symptoms.

Only other likely thing could be an injector bleeding down when the vehicle is parked for a time.

The best way to check that would be to hook up a fuel pressure gauge, (if you have a connection port), and see how long it takes for the fuel system to lose pressure.
 
Biever said:
Would I not get a code that one of the fuel injectors is bad
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If you have Forscan it will do a full fuel injector test and also will check all 8 injectors ( Live Time) ...if you have a Lincoln LS the Forscan app is a must
 
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