Lincoln :: Jittering Engine When It Is Warm

This is about my 1986 Lincoln Continental 5L with 93800 miles.

On Th Oct 8, I go in for my smog test. It failed. The timing has to be adjusted. I had to reschedule the test and the timing adjustment for the following Mon Oct 12.On Sat Oct 10, work needed to be done on my doors by a freelance experienced mechanic and at the end it killed my battery which I recharged.Mon Oct 12, I drive the car on the HWY 16 miles West bound then 19 miles East bound before I go for the timing adjustment and the smog re-test.While I was driving back East bound I noticed the engine sounding louder than usual yet I also thought it might a car driving by that was loud. I gave it little attention.At the exit ramp 19 miles later, when I accelerated after stopping, the car shook so much that it scared me. It was hesitating and jittering at the same time. It continued to do so while I reached the next stop over the bridge and while I drove up a hill all the way to the Smog Shop 4 miles farther.

After getting off the Freeway where I went up to 70mph I stayed between 35mph and 45mph to keep up with traffic on surface street until I reach the smog shop.There I revealed what the car just did and the mechanic advised that I get that fixed before I get it re-smogged. He was not interested in resolving the problem because it's an old car. Remembering my dad's best friend telling me several times that my dad never tuned the car since he had it in Dec 1995, I checked the car file and found that that was true and that only the spark plugs were changed in 1998 .That following Sat Oct 17, the freelance mechanic came and tuned the car with new plugs, wires, distributor cap and rotors, no timing adjustment though. Some electrical tape was wrapped over the hole on the vacuum hose nearest the distributor since he did not plan to bring a replacement in case there would have been an issue.

He claims the PCV valve to have passed his shaking check (Valve did pass the 1st smog test). He did a visual check of the fuel filter underneath the car in the back. The car ran smoothly after the job.On Mon Oct 19, before going back to the Smog Shop, I drive about 10 miles between 55mph and 65mph on the freeway and then 35mph to 45mph on surface street for about a half hour. All went well. I'm thinking the tune up fixed the hesitation/jittering/shaking problem. Once at the shop, upon adjusting the timing, the control module came apart; the plastic housing was broken in half (I have the broken part). The mechanic replaced it as well as the vacuum hose that was wrapped with tape. The car passed the Smog Test.Upon leaving the parking lot at the test station, I noticed the car hesitated/jittered just as it did last Monday, although somewhat subtle. I drove about 2 miles at 35mph, stopped and called the mechanic at the Smog station to tell him about it and he said that he had noticed the hesitation while it was running in the bay and he does not know what it could be since the car was tuned up and diplomatically indicated again that he was not interested in working on old cars.

I drove to the grocery store 2 miles away, spent about a half hour there and went home 6 miles away. The car had I guess cooled down some and therefor the jitter was subtle all the way home.In my view, and based on my experience on Mon Oct 12, it seems that that reaction (hesitation/jittering) occurs when the car reaches a certain temperature.I have not checked if the RPM jumps up or down whenever I accelerate when it jitters. One thing for sure is that when the jittering starts, it does it while the car is running and stationary, a bit more when you stop and go and more when you accelerate to a higher speed. On Mon Oct 12, I had the air on and turned it off shortly after the jittering was felt; that did not affect the intensity. On Mon Oct 19, I did not turn the air on at all.It seems that since the tune up, I can feel the car shift better and have never had issues with shifting anyways. Checked for slippage and that was negative.Fluids are always where they are to be. Motor oil and filter were changed on Oct 7.

Today, I've decided to seek a possible answer to my problem on the internet and remembered CarTalk.So far I'm finding out that it could be the Mass Air Flow Meter Sensor that needs cleaning, or an issue with the Temperature Sensor, the Balance Shaft, the Fuel Pressure Regulator, that a compression check may be needed. Keep in mind that I don't know if my car is even equipped with all that stuff since these findings are based on problem that people shared about their own cars. I must not forget to reveal that 2 of the old plugs smelled like gas and 2 were oily and very dirty (I know that the gasket on the left hand side needs to be replaced again).