5.0 Stumble

[trife86]

Ok well in efforts to get my merk up to top notch has been a pain. i still have a problem

Anyway at low RPM it shakes a good amount like a miss.
So i changed the spark plugs, wires, cap rotor, That helped out some.
but it was still there

Brought it to a mechanic he changed one fuel injector and the ignition module. Helped out some but still there.

Now i am fully clueless. It only happens at low rpm under a load. I checked the timing and have it at 12degrees base timing.
I have no idea anymore what it can be? Any suggestions?

[mrltd]

Could be torque converter. I'd ru some seafoam through it, and a couple bottles of injector cleaner. Also check the wiring on the coil for corrosion.

[LtMercDaddy]

check ya harmonic balencer too, the shaft on mine shattered and it would run rough at idle, swore it was a dead cylinder. if ya wanna check your cylinders for fire, start the car up and take the wires off one by one at the cap, when u take a wire off u should notice a change in idle should get lower, if u pull a wire and have no change, chances are u have a problem in that cylinder..... hope this helps

[trife86]

check ya harmonic balencer too, the shaft on mine shattered and it would run rough at idle, swore it was a dead cylinder. if ya wanna check your cylinders for fire, start the car up and take the wires off one by one at the cap, when u take a wire off u should notice a change in idle should get lower, if u pull a wire and have no change, chances are u have a problem in that cylinder..... hope this helps

Did the pull each wire off deal, All cylinders were firing. How do i go about checking the balancer, just see if it wobbles?

[trife86]

Could be torque converter. I'd ru some seafoam through it, and a couple bottles of injector cleaner. Also check the wiring on the coil for corrosion.

How would i tell if it can be the TQ converter?

I just threw a bottle of injector cleaner, i guess ill go buy some smoke show tommorow ( seafoam)

[LtMercDaddy]

Did the pull each wire off deal, All cylinders were firing. How do i go about checking the balancer, just see if it wobbles?

well, yeah you can visually check it, see it its wobbling, also there is a rubber insert that tends to get dryrotted and cracked.... mine progressivly got worse over a 3 day period, on the third day the belts got thrown and the crankshaft nose was spinning inside the balencer shaft. u could literraly spin the balencer and pully assembly without the crank moving, with this happening it wore down the crankshaft keyway almost flush with the crank....

[gadget73]

I had a bad balancer too, it didn't make the motor run rough but it did have some vibration at low speeds, and the pulleys were wobbling visibly.

My vote is on dirty fuel filter and/or clogged injectors. Change the filter and run some injector cleaner through it and see if it helps.

[trife86]

I had a bad balancer too, it didn't make the motor run rough but it did have some vibration at low speeds, and the pulleys were wobbling visibly.

My vote is on dirty fuel filter and/or clogged injectors. Change the filter and run some injector cleaner through it and see if it helps.

Ill run some more injector cleaner, change the filter, and do some seafoam and report back.

Thanks guys

[Mikeri]

I have had my 89 T/C since 1990. I have had the same problem described a few times. First, clean the injectors. I have tried everything and reccommend two things: First, Techron........very strong stuff and you should change your oil after a tankful of this stuff; and, Marvel Mystery Oil in the gas, which I swear by...use it every 3 months and have not had the stumble return. Also, learn to calibrate your TPS. You will need a volt meter. This is not hard to do. You will back probe the wires on the TPS, when it is lose, and rotate the TPS to a set point, and then tighten. I highly reccommend this procedure. Search this site for TPS Calibration. This removed my stumble at idle and smoothed shifts.