It runs rough, and no check engine light is on.

[Malibumax]

My 94 Aerostar runs rough/idles rough on start up, has no smoke coming out of tail pipe. When warmed up runs a bit better, but still sputters. No check engine light is on. Has 132,000 miles on it. Seems like cat convertor may be plugged. Any and all ideas on how to check this or what to do before I buy a bunch of parts/sensors would be greatly appreciated! Thanks!!

 

[CLTuna]

My 94 Aerostar runs rough/idles rough on start up, has no smoke coming out of tail pipe. When warmed up runs a bit better, but still sputters. No check engine light is on. Has 132,000 miles on it. Seems like cat convertor may be plugged. Any and all ideas on how to check this or what to do before I buy a bunch of parts/sensors would be greatly appreciated! Thanks!!

Start with plug replacement, then plug wireset, then vacuum hoses. just did my 1995 with near same issues for the second time in a three years. Plug changed fixed it. Hope it does same for you.

 

[Malibumax]

Do you think it could be a convertor issue?
Thanks for the quick reply!!

 

[CLTuna]

Do you think it could be a convertor issue?
Thanks for the quick reply!!

Couldn't give you an opinion on that. just had to share what has worked for me twice.

 

[Malibumax]

Thanks, much appreciated!

 

[BrooklynBay]

Which engine do you have? Did you check the intake manifold gaskets for leaks?

 

[Malibumax]

I just bought it, so I haven't checked too many things yet. How is the way to check the intake gasket?

 

[Malibumax]

It runs a bit better after it warms up... so that's why I'm confused.

 

[BrooklynBay]

Spray intake cleaner on the outside edge of the intake manifold gaskets while the engine is running to see if the idle changes. Do you know what the size of the engine is?

 

[Malibumax]

3.0 liter... I'll try the spray too.

 

[BrooklynBay]

The 3.0L engine doesn't usually have intake manifold gasket leaks like the 4.0L engine. Check the vacuum elbow under the air cleaner box for leaks.

 

[joshhemming]

My '93 3.0L did the exact same thing....hard to start, rough idle but better when warmed up. Someone on this board suggested completely removing the air cleaner box and checking the vacuum hoses beneath it. Bingo! One of them had cracked and slipped off the connector. It was the one which goes from under the box to over top of the engine to the fuel injectors or intake manifold, as I recall. The hose is specially made and formed, and expensive. I just pushed it back on the connector and taped in on firmly. It's held now for 2 years.

If that doesn't fix your problem, buy a can of MAF cleaner and spray on the contact/sensors between the air cleaner and the intake manifold. Sometimes it gets dirty and sends incorrect data to the computer. The MAF itself could be bad, too. It's easy to replace....screws on to the round tube between the air cleaner and intake manifold.

 

[Malibumax]

Thanks! I will check that first before I check anything else! Much appreciated!

 

[Malibumax]

Ok, *UPDATE*
So my ‘94 Aerostar
(4.0 liter/133,000 miles) had a bad misfire I found a bad plug. I replaced all plugs and wires. Most of the misfire went away, but here is still what is happening... the van takes a bit to start up, runs a little rough, blows out some white smoke (then clears up) then after a few minutes the van runs ok. THEN, as I start driving (and the engine warms up) the van runs a little rough again and vibrates a lot under load, mostly after 45 mph. As I let off the gas the vibration clears up, but then starts up again as I hit the accelerator. If I hit the pedal to the floor the vibration goes away, which makes me think this is a tranny/ torque convertor issue? But the misfire and 30 seconds of white smoke have me baffled. Am I needing a new engine? Is it a plugged catalytic convertor? Bad torque convertor?
I am showing no check engine light. I had the OBD scan just to make sure and no codes were found. The check engine light came on twice while driving, but lasted only a minute or so before turning off. I recently poured in a bottle of catclean, and have been running super unleaded. I just want it running smooth! I know there is133,000 miles on it, but we all know that’s nothing on these Aerostars! Any ideas? Thanks!

 

[Malibumax]

Also, I sprayed intake cleaner around the intake (while van was running) and there was no idle change. However, when I am driving and I get to my destination and put the van in park the engine revs up a bit and stays that way until I turn it off.

 

[don-ohio]

And you're getting NO check engine light? MAF sensor usually gives a code. How about the coil pack? How old is it?
don-ohio

 

[Malibumax]

I have been driving the van consistently over the past couple of days. I am on my way back to Buffalo from Georgia. The check engine light came on twice for about 30
Seconds each time, then it turned off. 98% of the time there is no check engine light on. When I replaced the plugs and wires I did not replace the coil pack. Would a faulty coil pack cause what still seems to be a little on and off misfire, 30 seconds of white radiator fluid smelling smoke on startup, and a heavy vibration under acceleration?

 

[BrooklynBay]

Coolant leaking into the exhaust system from a bad head gasket could contaminate the oxygen sensor.

 

[don-ohio]

Intermittent check engine light is indicative of a dirty MAF sensor. Been there.....suffered that!
An EXTERNAL leak such as a hose could be cause of misfire, but like Brooklyn says, white smoke OUT THE EXHAUST is almost always a head gasket or could be leakage into the intake manifold.

 

[Malibumax]

Would anyone know what causes a wicked vibration under load? Van runs smooth up to about 45, and at all speeds when I am
Coasting, but when my foot is on the accelerator the van shakes. I’m thinking u joints but when I jacked it up and turned the driveshaft (while I’m park) there is no clunking and only about a 1/4” of play. Seems solid, but could it still be the u joints? There is no check engine light on. I’m baffled. I hate chasing issues...