Rough engine idle under load

ford
escort

#1

A 1995 Ford Escort LX wagon with a 1.9l 4cyl engine and automatic trans runs great until you stop in drive. Then the engine starts to rough idle vibrate enough to feel throughout the car. It is greatly less in neutral but apply load (headlights on…a little, AC on a lot) and it’s there. For a year now; all motor and trans mounts (softened it) spark plugs, wires, O2 sensor, found and fixed a vacuum leak in a fuel vapor recovery hose to the intake manifold have made no difference. I’m down to (1) Idle air control (2) Mass air flow sensor (3) EGR valve and I don’t know what else to consider. It’s driving me nutz… What do you think?


#2

How about fuel and air filters? Check the fuel pressure. You found one vacuum leak - have you been able to be certain that there are no others? (How?) Any check engine light? Codes?


#3

What did you say the fuel pressure is at idle, in Drive? How about at 2000 rpm in Drive? Does it drop off a little?


#4

It sounds like you might have a locking torque converter stuck in the locked position.


#5

Considered but no factor. Remember, it will do it UNDER LOAD (in neutral) including electrical load on the alternator (headlights/highbeams) and or AC compressor engauged.


#6

Fuel and air are kept new per maintenance intervals. No check engine light. I need to plug the car in at Auto Zone (free) and get any codes if they exist. Fuel pressure has not been checked! Vacuum is secured as I plugged every thing up bit the EGR port which is still a suspect.


#7

Fuel pressure. Fuel pressure. I need to research what it should be AND CHECK IT LIKE THE MORON I AM!!!


#8

As a '95 the system is probably OBD-1 rather than OBD-2. Autozone probably can’t handle it. Some OBD-1 systems had a way to pull codes without a reader (e.g. via a key on/key off process with the engine light blinking out a code) - I don’t know if these Escorts do that or not.


#9

I have learned today (professional mechanics DO have their place in this world) that of the three mounts I did replace (right upper motor and left lower front and rear transmission mounts…) there is a fourth mount at the top of the transmission (on the left) living under the battery tray that I haven’t replaced (THE FORD PARTS LIST DIDN"T SHOW IT because it’s discontinued). Picked an after market one up today along with a can of MAF cleaner. I’ll keep y’all posted on the results.
I wouldn’t want anyone else to have to go through this!


#10

Make up your mind. Is there an engine/transmission vibration problem; or, is there an engine performance problem? Which do you want to fix?


#11

To check the EGR valve, remove the hose to the diaphragm and apply vacuum (suck on it). It the idle goes further south, it’s probably fine …and at least functional within the mechanism itself.

The MAF cleaning (be careful) and AIS motor will probably cure your symptoms otherwise.


#12

Right now, I am suspecting an engine idle problem CAUSING the vibration symptom…


#13

Thank you very much. This kind of constructive advice is what I came here for. Now all I need is a nice block of time to spend trying these things that have been suggested. (I couldn’t even listen to Car Talk today because I had to work). I’m recording it online from the archive as I’m typing this!


#14

Classic test for misfire on any thing more than four cylinders (if you cant tell your misfiring on a four cyl well…)is to put the car in gear and hold the brake and give it just a little gas,misfire will be very evident and it sounds like you fit the bill.


#15

I’ll try it. If I pull plug boots one at a time (which I have already done) it runs ratty with no load…