'94 gt shaking!!!! - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

applehead · 12-28-2009, 08:12

With my 5.0 in park I apply pressure on the gas pedal and get a tremendous shaking in the cabin. Engine does not jump or lift which I assume means mounts are okay. Manually increasing rpm with accelerator cable in engine bay seems to be okay. Initial startup begins with high idle and the shaking but settles down to normal idle, no shaking. When I reach cruising speed on the freeway everything seems to run smoothly. Replaced idle control valve or sensor about a year ago. Any ideas where to start?

speaker_king · 12-28-2009, 13:20

EGR....TPS...... They both can cause this. Dont know if your car has a MAF, but it will cause this also. But it only shakes while your in the cabin... Have you checked the trans mount? Mabey you just dont know its shaking cause your not in there. Also, a borken exhaust mount will cause it to vibrate against cabin.

applehead · 12-29-2009, 18:05

i checked underneath and everything looks tight. The shaking occurs between 1000 and 1500 rpm. I sprayed carb cleaner throughout the engine but I do not know what I should be listening for or expecting. Anyway nothing seemed to change as far as I could tell. The mustang does have MAF. Should I remove the actual sensor inside the tunnel or baffle of the air filter housing and spray with cleaner or just spray the connections? Thanks for any info. Next I will check EGR and TPS. Doing this in between work and 6 year old son on vacation from schooll so bear with me. Much appreciated.

speaker_king · 12-30-2009, 13:43

I wouldnt recomend removing the sensor from the housing, but thats how i clean mine. Its just really easy to bent the wires on the actual sensor. An easier way is to spray a can of compressed air into the housing. DO NOT spray the connections.

It kinda sounds like your having more of an ignition problem. Whens the last time you gave your car a complete tuneup, wires and plugs?

applehead · 12-30-2009, 16:36

I just changed the plugs and wires hoping that was the problem. Everything is connected properly but the problem is still there. Still need to check egr and tps...will get back.

applehead · 01-02-2010, 19:24

Okay, Thanks for all the help and suggestions. As for now it looks like I will be looking for a reputable mechanic in the San Diego area to tell me what the problem is. Then I can decide if the fix is a diy. Once again, the car starts in a high idle with cabin shaking then settles down to about 800 rpm. When applying pressure to the pedal I get major shaking in the cabin between 1000 to 1500 rpm. At higher rpm the engine runs fairly smooth. I may decide to replace the egr valve but this is a guess as to whether this is the problem. I did replace the idle air control valve sensor recently. It does not feel like the car is missing when I press on the pedal and all the replaced wires and plugs are inserted correctly. Could it be the throttle position sensor. Would this cause shaking or just misfiring? Harmonic balancer looks fine, no loose pieces or wobbling or noise, but do I need to take a closer look? If this is a vacuum leak then this is my achilles heel. I do not know the first thing to do. Whew!!! Thanks for listening. Any more ideas would be much appreciated. I would really like to fix this problem myself.

applehead · 01-11-2010, 05:34

Today I tackle the harmonic balancer. Will replace and hope this solves the shaking. If not then egr is next??? Good idea or not? Should I do egr first, then balancer? Does egr even remotely cause violent shaking of the stang? Have replaced pcv and fuel filter and checked all vacuum lines and also replaced purge solenoid.

speaker_king · 01-11-2010, 19:26

A faulty egr or tps will cause "any" car to run lean or rich. Its just only noticable at certian rpms. (usually lower)

If there is an o'rielly or autozone around you, they can scan it for you and see what codes come up. Even with the engine light off.

applehead · 03-06-2010, 16:57

Thanks to all,

Problem solved.
It was the harmonic balancer after all. It had deteriorated and caused the timing to shift 180 degrees. Replaced, and with new plugs and wires and cap and roter it purrs like a kitty cat.

Thanks again for all the help and suggestions.

Next up... new headers...is this an easy replace?