Car idling/revving rough

[fiveomar]

5.0 Running Rough

Hi all, about a couple months ago my 5.0 started running rough. The idle is rough and bouncy, and you can feel the car shaking a bit. When revving the engine or accelerating, there's hesitation/missing (the car putters). Also let's say I'm cruising at a steady 3,000rpm...I can see tach needle twitch/bounce.

I tried cleaning the MAF, cleaning the IAT sensor, cleaning the IAC, cleaning the throttlebody, resetting the computer...all to no avail.

Any other suggestions...setting the TPS voltage? What does this do?

Thinking it may be the distributor? Is there a way to test the distributor or visually inspect it for wear?

I'm thinking about getting a used distributor just to try and see if this is the problem.

I'm just trying to get a list of possible causes and ways to diagnose. Would really like to avoid going to the mechanic to diagnose this.

Thanks.

 

[1TallMF]

Check your spark plug wires, every single time I've had similar problems, it has been related to improper plug/wire boot contact or just bad wires. Try having the car idle in a pitch-black location at night, open the hood and spray a mist of water and look for any arcing.

 

[sn95coupe]

I am having the exact same problem but in mine if i am above 3500rpms its fine i have a t5. last week i power washed the under side of the engine and all the problems went away for like an hour

also i am having problems with my speedo, it only works for like the first couple miles then just stops working.

any help would be great

 

[Blackened302]

have your codes pulled at Advance/Oreilly/etc.. it's free and is a great place to start

 

[sn95coupe]

i had them pulled but nothing came up

 

[1TallMF]

I've had that problem on and off since I bought the car, and never had any codes for anything. Wires were the culprit every single time. But I already said that, haha.

 

[HISSIN50]

If the spark plug light test Stephane mentioned doesnt yield anything, run a cylinder balance test. This checks cylinder contribution.
You will do this after retrieving KOER codes.

If you remove the dizzy cap, you can spray electrical contact cleaner around the bowl of the dizzy. Sometimes this helps PIP issues. If you note lots of metal dust in there, that suggests the dizzy bushing is on the outs (it takes the PIP with it most of the time).

Good luck.

 

[sn95coupe]

what wires were the cause?