1.Is the engine missing? Does it shake while giving it gas????
2.Does the Dash shake or vibrate while idleing???
3.Does the engine move alot idleing and putting into reverse an drive???
If it does then you need motor mount's/maybe crossmember bushing's.
Yes tune up could be an issue.
Is it worst in drive??? If so then you need to check the rear lower tranny mount and the bushing's to the crossmember. Can you do this kind of work?? Also the engine mount below battery tray need's checking.
Do you have an auto or a 5speed??? I will help you check from there. Have you crawled under to look at them? If you have a haynes there is a page with the location's. Page 2a-35 Fig. 19-4. I know it says 1.8 but they all are the same(even 3rd gen). Pm me if need. Email whatever.
Ok lets rule out how the engine run's first. Last time it was tuned up? What was replaced? Fuel filter change? Last time You checked to hear or spray down for Vaccum leaks. Yes the elbow is a problem area. Quick fix is the Junkyard, grab a 3rd gen hose and valve. Looks better also. One piece hose.
With the car in drive(ebrake and foot on pedal) do you have vibration in the dash(idleing)? With you doing this or someone else go from reverse to drive an check the engine for movement front to rear of engine bay. Which ever moves the most is the likely culprit. But if it was me I'd be checking(replace) the lower tranny mount's for sure. If 1 is bad the other isn't far behind. They are less than 20.00 apiece. The upper engine mount's are less than 25.00 apiece. Can be done by you on a saturday.
The lower ones you need the extra hand tho. Safety also.
Did you do all 3 (oil,intake,fuel tank) ? If you did the intake an noticed the difference right after, then you may have an egr problem(carbon buildup). If you had a check engine light then more than likely. Even if intermitent it may not show(check engine). Wouldn't hurt to take egr loose an clean tube an intake. That would also make it run better an get better gas mileage. Seafoam does wonders. When you get a chance run some water next to finish decarboning the cyclinders. I usually do this a day later. And next change fuel filter ($10.) and plugs($2.43ea. autolite ap104,Wallyworld). Tank trash and carbon will get to both. Give it a week on them before you do this. Wish you all the luck.
I'll be watching this thread. I heard it was a TSB on the auto 1.9L cars, but maybe I read wrong. Mine shakes like crazy in Drive, not in Neutral or revving the motor. Only at idle. Let me know if you fix it!
I have a 94 escort with a 1.9L engine and I had a similar problem and did a lot of research on this to save a few bucks. The problem with my car was the idle air control valve. The idle control valve is used for controlling air flow when not adding gas, something to make the car burn less gas. After thousands of miles that valve can get sticky. Some can be cleaned, mine had to be replaced. It was around 50 bucks. Now it runs smoothly hardly can hear the engine. If that is replaced and still you have problems than make sure that the egr valve is cleaned.
Yeah, That would help. Think about all the gunk you've broke loose(tank and Cylinders). Seafoam will disolve carbon an varnish. Tuff stuff. I have soaked bad lifters in this stuff an it was clear when I started. End was blackish grey. Varnish was gone an shiney.Put it in your oil an watch the color change. The oil will be black an valve cover area will clean up also.(inside). Does wonders for ticking lifters. They usually pump up quicker after setting awhile.
If you still have any vibration check the other things stated here. They can cause issues also. Idle air sticky is usually a low idle or fall on it's face type thing. Where it can't respond quick enough. Egr will cause a rough idle too. But computer most of the time will catch it. Still wouldn't hurt to clean if this was a cure. Meaning carbon in intake an egr tube possibly. A stopped up egr can cause the engine to over heat an burn valves, plus bad gas mileage.