Rough Idle Only in Drive - Neutral okay

[jarnol]

I have a 95 Contour with 2.0 L 4 cyl, AT, A/C, 113,00 miles
The engine has a annoying idle problem that shakes/shutters the car when idleing (in Drive) and stopped (like at a stop light). The shake/shutter goes away when put in neutral or park. When in drive the engine shutters whether A/C is on or off. The shutter goes away when slight accelerator pressure is applied. Engine runs extremely well otherwise. New O2 sensor eliminated all trouble codes.
My trouble/ fault code reader only indicated an improper throttle position signal during the throttle response part of the Key On Engine Running part of the test (pressing the accelerator pedal). So I suspect the Throttle Position Sensor – but I am reluctant to replace it unless I can get confirmation that this could be the problem.

[beyondloadedSE]

have you inspected the motor mounts?

[jarnol]

Originally Posted by beyondloadedSE

have you inspected the motor mounts?

A mechanic checked the motor mounts and said they had small crack - but that it didn't go all the way through.

[chasmanz28]

Originally Posted by jarnol

I have a 95 Contour with 2.0 L 4 cyl, AT, A/C, 113,00 miles
The engine has a annoying idle problem that shakes/shutters the car when idleing (in Drive) and stopped (like at a stop light). The shake/shutter goes away when put in neutral or park. When in drive the engine shutters whether A/C is on or off. The shutter goes away when slight accelerator pressure is applied. Engine runs extremely well otherwise. New O2 sensor eliminated all trouble codes.
My trouble/ fault code reader only indicated an improper throttle position signal during the throttle response part of the Key On Engine Running part of the test (pressing the accelerator pedal). So I suspect the Throttle Position Sensor – but I am reluctant to replace it unless I can get confirmation that this could be the problem.

i have the same problem, what is it with all these threads im reading about idle problems with these cars? ive changed the MAF, new plugs and wires, new o2's, new pcv valve, and i still get the virbration when in drive, its driving me crazy, can anyone think of anything else it could be? BTW its a 96, 4 cyl with the dohc

[barretire]

Originally Posted by jarnol

I have a 95 Contour with 2.0 L 4 cyl, AT, A/C, 113,00 miles
The engine has a annoying idle problem that shakes/shutters the car when idleing (in Drive) and stopped (like at a stop light). The shake/shutter goes away when put in neutral or park. When in drive the engine shutters whether A/C is on or off. The shutter goes away when slight accelerator pressure is applied. Engine runs extremely well otherwise. New O2 sensor eliminated all trouble codes.
My trouble/ fault code reader only indicated an improper throttle position signal during the throttle response part of the Key On Engine Running part of the test (pressing the accelerator pedal). So I suspect the Throttle Position Sensor – but I am reluctant to replace it unless I can get confirmation that this could be the problem.

Possible vaccuum

[chasmanz28]

Originally Posted by barretire

Possible vaccuum

yeah i checked for leaks none. What should be the RPM be at idle? Is it 1100? Because mine is at 800 in park when warm and when i put it in drive it drops to 600, im thinking the idle is to low causeing the vibration

[myconsvt]

no if it only does it in drive and not in neutral your motor mounts have nothing to do with it it would be your tranny.

[mastermech]

use a volt ohm meter, if you want to be sure the tps is out of spec. put the meter on a medium ohm setting say 20,000 and connect one meter lead to one wire on the tps (disconnect the harness) and the other lead to the another then open the throttle. you are looking for a smooth changing of values on the meter. if it jumps around and is erratic than the tps is faulty.

[lrosewarne]

Sounds to me like faulty injectors, could be the tranny if it was low on oil or loosing pressure from an oil leak which would cause it to slip in and out of gear. but i doubt it simply because you sound half switched on and would have picked that up.
When u put it drive, the engine is loaded a little which drops the rev enough for you to notice the miss. i think its a faulty injector which is dribbling (not closing) which would cause a miss fire kind of feel at low idle. go to the local part store and get some injector cleaner to add to your fuel tank. the best way is to overhaul your injectors. not real expensive
Try leaving your car idle in neutral and adjust the idle down to the same rev's it idles at while its in drive and see if it starts to miss.
I dont think its the throttle postion sensor because that would give you a different problem. not a miss fire feel
It could be your dizzy cap. might have carbon tracks on it. get a mate to hold his hand on the dizzy while its idle. if he yelps from a little ZAP! change your dizzy cap. and/or leeds
Let me know your out come.

[darrellf40026]

I have a 98 Contour that does the same, but it has did it since I bought it and that was 30,000 miles ago, so its all good. lol

I'm not too sure what it is that causes it either, but I'm a firm believer in the "if it ain't broke I ain't fixin it" motto.

[RoB51988]

I have a 97 GL and mine does the same thing. Theres cars are junk after 80k. My A/C doesnt work in idle because the idle is garbage on all of them.