Weird "bucking" issue with my 2001 Grand Marquis

[meep]

Easy diagnostic to put a 1/3 dose of lubeguard red in the transmission, if that changes things then you’re looking at a TCC or valve controls.

Though the electrical issue for 30F is v interesting. Add your own ground harness as an experiment?

Agree with oddities also with spark delivery. Colder, denser air plays a role. Consider tightening plug gaps just a hair as well.

 

[SwampSurvivor]

Easy diagnostic to put a 1/3 dose of lubeguard red in the transmission, if that changes things then you’re looking at a TCC or valve controls.

Though the electrical issue for 30F is v interesting. Add your own ground harness as an experiment?

Agree with oddities also with spark delivery. Colder, denser air plays a role. Consider tightening plug gaps just a hair as well.

I'll check plug gaps next time I have them out.

Is lubeguard going to permanently damage anything? I worry when it comes to older transmissions and additives.

When I bought the car I did add an extra ground from the alternator to the battery (basically an additional engine ground). From the factory they ground to the body then back to the battery. The body grounds aren't the best and the interior lights / clock dim when the turn signals blink as it is ...

 

[Rob_Roy]

I had what sounds like the same problem with my 2001 Grand Marquis. The issue ended up being the DPFE sensor. When I replaced it I remember the old one had a lot of moisture in it. Should be plenty of info on DPFE issues over on crownvic.net

 

[SwampSurvivor]

I had what sounds like the same problem with my 2001 Grand Marquis. The issue ended up being the DPFE sensor. When I replaced it I remember the old one had a lot of moisture in it. Should be plenty of info on DPFE issues over on crownvic.net

My Taurus started doing it and eventually set a code for EGR flow. I changed the sensor and it never did it again.

I said earlier that I changed it but now I'm not sure where the one I used came from. I don't have any receipts from any orders. Maybe I didn't actually repalce it. I'll buy a Motorcraft one and throw it on in the fall.

To me, it really feels like the engine is getting too much / too little air for a split second which could be the sensor causing the EGR to do all sorts of crazy things.

This is the last year the car needs an emissions inspection. I have half a mind to just block off EGR entirely.

 

[SwampSurvivor]

Now it does something similar taking off from a stoplight. If I get on it hard from a stop where it's been sitting in gear for a minute it acts like I took my foot off the gas hard, then on hard , off and on then finally goes.

It's not acting like it's a coil issue. It can lug along at 30MPH in overdrive smooth as silk. That's where a weak spark issue would show up.

This is a fuel pressure regulator right? Looks like one to me ... it REALLY feels like an issue with a fuel pressure regulator ...

There is no Fpr listed for this car

Rockauto has this listed but says on tank

 

[D60]

Now it does something similar taking off from a stoplight. If I get on it hard from a stop where it's been sitting in gear for a minute it acts like I took my foot off the gas hard, then on hard , off and on then finally goes.

It's not acting like it's a coil issue. It can lug along at 30MPH in overdrive smooth as silk. That's where a weak spark issue would show up.

This is a fuel pressure regulator right? Looks like one to me ... it REALLY feels like an issue with a fuel pressure regulator ...

There is no Fpr listed for this car

View attachment 275185


Rockauto has this listed but says on tank

View attachment 275186

That's your FPR, yes. Have you checked actual fuel pressure yet?

 

[SwampSurvivor]

That's your FPR, yes. Have you checked actual fuel pressure yet?

I had a gauge that would thread onto the schrader valve somewhere ... lost it. I'll rent one and figure out how to take a reading while driving. I don't think this car reports back to the computer what the fuel pressure is.

 

[SwampSurvivor]

I ended up putting a Dephi fuel pump in the car. Never got to check the fuel pressure. Delphi seemed to be the best brand.

It died on me once on the highway. A couple times taking off from stoplights I gave it gas and it sputtered and died then was hard to restart. One time it wouldn't start at work. I checked the fuel rail and there was nothing for fuel coming out. It did eventually start after cycling the key a bunch.

I've had other fords and they always started strong. Once they fired off they ran. This car has always coughed a bit when the engine starts. Now it doesn't do that any more.

Maybe the fuel pump was going out for a while? Or weak for a while? It wasn't the OEM pump - the little fuel line section was from 2007. Weird that the factory fuel pump failed in 6 years, however. Or it was old stock.