Engine Runs REALLY REALLY ROUGH Please Help

[bzackrie]

Ok guys, I was working on my truck today, I cleaned the MAF with carb cleaner (i think that was my first mistake?) and next I used BerryMan Universal Additive (http://www.berrymanproducts.com/Default.aspx?tabid=142) and poured that thru the Brake Booster Vacuum Line. Was working great. I Then go to drive it and it hesistated like normal which was expected because it was clearing out all the carbon (was really smoky) I then start driving it around and it continues to idly really really rough and when you put your foot on the gas it sputters bad but when you get going it smoothes out. When I was on the highway though when you continue to accelerate up to 65 if feels fine but once it shifts to the last gear it shakes bad and just runs like crap. I dont think it was cleaning the intake sytem but I actually think its the MAF? I was also reading and they said sometimes when people clean the intake system if its dirty enough it could cause the O2 sensor to go bad which also could cause the engine to run rough. So im guessing it could be a combo between the MAF and O2 sensor but Im wondering what you guys think?

 

[dogboy]

I'd check the spark plugs. I had a 2.3 that sputtered under acceleration and I replaced the plugs and it ran fine afterwards. Is your Check Engine Light isn't on,? I a assuming it isn't, you probably would have said so if it was. But if it is, and your truck is a 1999 (I think) or newer, I would take is somewhere to get the codes pulled. All of the Autozone's around me will do it for free. And don't go to Ford, they will charge you for the exact same thing as far as I know.

 

[bzackrie]

Would this problem though be safe to say that it didnt come from cleaning the intake sytem through the Brake booster line.

 

[Joe400]

I dump (slowly) a can of seafoam through my brake booster line every few months. A lot of loose carbon could have fouled some plugs. I would pull some plugs and see what they look like, then i would try unplugging the mass air sensor and see if you have positive results. My mass air sens. went bad a few weeks ago and the truck barely idled. good luck

 

[MAKG]

Would this problem though be safe to say that it didnt come from cleaning the intake sytem through the Brake booster line.

Not at all.

Another potential fault is a warped or burned exhaust valve. Which can very easily get caused by breaking stuff free in the combustion chamber, and having it caught in the valve seat. A leakdown test can easily detect this problem.

There is a lesson here -- if it ain't broke, don't fix it. The correct way to remove carbon from your combustion chambers is with a razor blade or wire brush (for cast iron heads). Engines in proper repair do not accumulate significant carbon.

 

[bzackrie]

its a 96 with 77K on it....does that improve my chances of it not being a warped/burned out exhaust valve. Have you heard of this happening alot? Whats the actual likelihood of this?

 

[bzackrie]

Ok, to start off with I am still going to get new spark plugs tommorow but I took them all out today carb cleaned them got the carbon off and stuff and also made sure they were at the right gap. I did notice that the plugs on the right right facing the truck (cylinder 4 5 6) were alot dirtier, they had crud on them. I reinstalled them all and the truck started easy, like it was doing before with the rough idle. Even though my truck starts easy it still has that real rough idle, could it still possibly mean fouled plugs even though easy starts?

 

[reno]

replace them plugs, and get a can of non residual cleaner meant for the MAF sensor and clean it again. Did you touch the wires on the MAF? Was the key off when you removed\replaced the MAF? If it was on and the MAF had power, you could have grounded it out. Is the gasket good on the air box where the MAF bolts to? The snorkel tight? Check the Vacuum hoses for leaks.

 

[djurs]

Any time you suspect the MAF sensor to be at fault you should disconnect the plug from the MAF, and see if it fixes the problem.

If the MAF goes bad it sometimes reads very high flow... the result is the engine dumps a lot of fuel into the cylinders, and you run very rich, or barely at all. So, naturally when you get it opened up on the highway (if you can get it to go that fast), it smooths out, because the fuel air mixture comes back into balance.

 

[MAKG]

Well, virtually any rough idle condition is better at higher RPM, because of the flywheel.

Burned or warped valves are not caused by wear. They are caused by dirt in the seats. You test for it with a leakdown test.