please let me know how many miles and if you checked for trouble codes. If there are trouble codes for misfires the coil may be the cause. I have seen a few that misfire when hot and only one cylinder. I use a spark tester at the coil to verify if I lose or lost spark to any cylinder. At the dealer we have an advanced scanner that lets us check each cylinder with a power balance test. Trouble codes can help us know what cylinder is the trouble too. I would check the fuel filter and fuel pressure if no misfires or misfire codes. We should have 26-45 psi engine running. If we still do not confirm anything there are more tests we can do.
lets start here
let me know what you find
There are no misfire trouble codes. The engine runs smooth at low speeds and idle. A few weeks back the check engine light came on and trouble code said it was O2 sensor. After resetting the light it hasn't come back on.
It sputters worse on the parkway at around 70mph when going up inclines and not much on level roads or at all going down grades.
if you can tell me the exact code
If you can check the fuel filter and fuel pressure
we should see 26-45 psi. If I suspect a fuel pressure issue I attach the gauge to the fuel rail and run it under the wiper arms with the hood down(not latched fully) and test drive to see if fuel pressure drops.
I don't have the trouble code. The guys at Advance Auto Parts read them.
I'll have to rent a fuel pressure tester & do this tomorrow evening. Can we continue this then?
yes. The more info we get from tests the closer we will get to solving this issue.
advance probably uses a minimum function scanner, not the best.
we can go back and forth as long as it is needed
you can check the fuel filter first. If it is heavy and rust comes out it is time for a new filter. You can even try to blow through it. I just had to replace my filter on my 2000 Taurus, started to ping and lost power. Almost totally clogged.
How do we continue this conversation tomorrow after I check the fuel pressure?
There does not appear to be a fuel rail test port on this car.
They do have adapter kits for this. I have one with my pressure tester. I have a hose with a T that my gauge hooks up to.
mine looks something like this. If you have a test port it will be on one of the rails
I bought a fuel pressure tester. It didn't come with that adapter. It means I'll have to go back to the auto parts place and see if they have one. Here's another question. Is it possible that overdrive is malfunctioning and it only seems like the engine is sputtering. The problem mainly occurs at around 70 mph on the parkway. I have shifted out of overdrive into drive and the rpms jump to around 3400 rmp and the sputter or shudder goes away.
The transmission fluid is reddish brown. As far as I know it has never been serviced. Has about 140,000 miles on it.
well. tough choice to make. Either you can try a trans flush or try adding some trans additive. With 140k and not knowing if it has been serviced there is a chance changing the fluid will create more trouble. when clutches wear the friction material comes off. sometimes staying in the fluid keep the trans from slipping, changing the fluid can allow the trans to slip.
I would try adding a trans additive first.