98 cavalier running rough

[Rtstrider]

Hey I just changed the plugs/wires on my gf's 98 cavalier 2.2. I also did a piston soak overnight with mmo and cleaned the ground to the battery tray due to corrosion. After changing the plugs/wires the car is now running rough and the coolant gauge has been going crazy. I have tried seafoaming but that has not fixed the issue. This originally started with the car running rough at highway speeds which led me to think it may be the fuel filter. Has anyone run into this before?

P.S. the plugs/wires are AC Delco and they are gapped at .060. Plus I just changed the oil to 3 qts of oil with 1 qt mmo.

Oh and also she has a habit of letting the car run below the E mark. This car has around 150k on it right now.

 

[chubbs1]

Did you account for the thinning of the oil with MMO? Is MMo something you run often? That is more than the recommended 20%. I would change in 1k and put a thicker oil in her and see what happens.

 

[Rtstrider]

Yeah have run this twice before without issue.

 

[Rtstrider]

Could this be the coolant temp sensor going bad? Also there have not been any codes thrown. Anyone know how many coolant temp sensors this car may have?

 

[FL_Rob]

Fuel filter is original ? if so change it, plus running below E lets all the junk in the bottom of the tank get sucked through the pump.After the filter is changed you might wanna run a fuel pressure check.


edit: when my pump went out under similar circumstances,no code was thrown it just ran like %#$%# ,then died a week later.but it did idle ok that week till it wouldnt even turn
over.

 

[Rtstrider]

Well I think the main culprit I'm going to start with here is that when the car starts running rough the coolant temp gauge drops below the C mark. Can a coolant temp sensor cause issues like this? Yes I have googled this as well and all I have come up with is rough idle, black smoke, and hard starting after the car is warmed up.....I guess it's worth a shot as Oreily's has the sensor for $11

 

[RegDunlop]

Maybe double check your wires make sure they are all going from/to the correct position

 

[mechtech2]

Run Chevron Techron or similar newer cleaners THROUG THE TANK!
Forget the silly down the pistons or in the PCV nonsense.