Its only when in drive and foot on the brake like at a red light it shakes. When in park at idle its fine. not sure what it is. The mechanic said the engine mounts look fine. This all started after the head gasket repair. Truck has 140,000 on it. It could be the mounts or trans mount but it never did this

 

I know theres a (TCC) solenoid on the transmission that is in acted by the brake to put the torque converter in neutral and if that is stuck or doesn't work right it will do that but I would imagine it would also shift a bit rough. The one guy posted about headers tightened under tension can cause it and if your headers were just replaced I would definitely think it would have something to do with it.

I know I just tried to take off my serpentine belt but I could not budge the tensioner to get the belt off and test it. Maybe it was me but I couldn't move it so that's one test won't be able to do.

I did take off the EGR hose off the solenoid and it is constantly sucking to the EGR valve. I thought I noticed a slight change when I had it unhooked but couldn't be sure. I do now when it was hooked up and I went to the white hose coming out of the solenoid to the other side of engine it was sucking in making me think the EGR solenoid is not working cause I think it is suppose to be closed when at idle and warming up, which this was and open when the engine is at operating temp.
If someone can clarify that, that would be great! Thanks
I just hope its not the EGR cause mine is on the back of the intake up under the firewall and cowl. GRRRRR!
I did not here a click when I stuck my finger over the green hose that went to EGR that would be a sound that it closed but like I said its way back there.

 

Went to a garage today and they checked the truck out for an hour and couldn't diagnose the problem. They said it exists-lmao.
They said bring back and drop off so they can spend more time with it or just wait until the thing gets worse. ha!
Gonna get an oil change and put in 5W/20 with Lucas and see if that helps at all. I am sort of leaning in the direction of the timing or the cpm program.

Came off the interstate and stopped and she was running beautifully, then she started to shake again. Then later at a stop it was perfect then started after a minute. I even thought maybe there was a voltage problem which is causing interference with the engine.

I'll figure this thing out if it kills me or trade it in on a Lincoln Mark LT. lol

 

Keep the Lucas OUT of that engine. You shouldn't need any additives if you are using the correct oil.

 

Thank glc. Will do.

I have a bottle of the oil additive I was gonna use too when i get the oil changed at Ford tomorrow. Hopefully they will be able to tell me what's going on with the shake.

I put the fuel additive cause I thought it was the injectors but it doesn't seem to be the case, at least not that a fuel treatment can fix.

Thanks again.

Changed the dealer I am going to tomorrow. Figured a Lincoln dealer for service would be better, and better waiting rooms I'm sure. lol

 

This shake is driving me crazy i cleaned my iac still no good i also did notice its shaking in park but not as bad you don't feel it as bad when in gear and foot on brake.

 

Did you do the motor mount test? needs two people. Just put it in gear and keep foot on brake and rev up a lot then in reverse and the person watching should be able to see major movement if it is the mounts.

I would check the booster vacuum lines. Hopefully its nothing major cause I'm sure there was a reason why head gaskets were replaced and if it warped the head and machine shop didn't plane it right it could of warped a cylinder.

Did you loosen and reattach the headers to see if that might be the cause?

I know with out codes it really sucks to diagnose. I just think if you feel it in the pedals then it has to be the brake system.

 

The head gaskets were replaced do to intimate heat problem. The heads were rebuilt and got a valve job.
I asked the shop to check motor mounts they said they looked ok
No i did dot try the exhaust yet.
Not feeling in the pedals only in the seat and you can see the center console shake
Sorry for asking question in your post thanks for the help

 

Well I wasn't expecting this! At Lincoln garage and was just told the #3 cylinder is almost dead! It will be cheaper to replace engine rather than fix the cylinder so I have to decide if I want to spend 7k on new engine or trade it in on another vehicle.
That freagin sucks. Looks I have bad choice in vehicles. I should've kept my Lincoln Ls and replaced the transmission. I'd have a few grand in my pocket after the tranny. 😭😭😭

 

Do a compression test to make sure the latest diagnosis is correct before you do anything else. If the compression is low, then you know what the issue really is. I'd check all of them while you are at it. If the compression is low, it could be a valve problem and you may not need a whole new engine.

Did you say how many miles are on this engine?

 

Hers the readout they gave and I asked about manual compression test and if the PCM could actually cause this by bad signals and they said no because only .01% of time its the PCM and manual test they give you a variance but their "15K dollar computer laptop" gives the "only reliable" reading.
"" their words lol

My mechanic wants to do an induction cleaning to make sure that its a dead cylinder and the dealer that sold me the truck said they can possible help out with the cost of repair. I am so hoping Lincoln is wrong but I haven't delay with them before so I don't know.

Just turned 130K miles today

If new engine is the scenario I'm thinking of trying ceramic additive to improve compression and postpone the engine replace for a little extra while. I'm hoping they know hat they are talking about cause 5% compression loss doesn't sound like much and to have a miss doesn't seem right to me. But what do I know!

 

Sorry to here same thing happen to with the head gaskets it was a couple of days after I bought it I found out

 

5% less compression than the best doesn't mean a "dead" cylinder. It still could be a valve problem. I think I would at least take off the valve cover and take a look.

Way back, I bought a used 1969 Chevelle SS396. A valve was clicking so I tried to adjust it. The engine cut off. So, I looked a little closer to discover that the cam lobe was worn almost completely off and the lobe had worn into the lifter and it was adjusted down and acting like a solid lifter. A new cam and lifters and the engine ran great with 180 psig compression in all 8 cylinders.

 

I have an appt for the morning to do an induction cleaning to rule out sticking valves or clogged holes. That way it will help me to decide whether to trade it in on another vehicle or to bit the bullet and replace the engine.

Only issue with trading it in is the slight shake at idle and gear. Hell they might not notice cause Ive had garages not notice it. lol

So much for being a simple EGR problem. (ARGHHH!)

UPDATE

I just had induction cleaning done and the shake is less pronounced. Seems to have disappeared some but other times you can feel it slightly. Much much better than what it was so hopefully it will dissipate after a tank of fuel.
Even my mechanic said it doesn't sound right that a 5% loss of combustion in one cylinder would cause a shake/miss.

I'm happy its better so I have time to decide whether to keep it or trade it. I'm leaning towards saving up 7grand and in a few years just replace the engine. Its a freakin nice truck! lol

Thanks everyone for your help and if it goes away completely or comes back I will repost here as to try and help others diagnose their issues. Cheers!

 

What about upstream O2 sensors? Have they ever been replaced? I just replaced mine and the idle quality, general power and gas mileage all improved. I was told the O2's would get "lazy" over time and not respond as quickly as when new. No codes or anything displayed. My truck showed symptoms right after a plug change at 72k.