87 3.0L-- rough idle --HELP!!

[ziocles]

When it *does* start, it chugs and chokes like it's not getting enough fuel; 'feathering' the accelerator only extends the agony, and steady depression of the pedal only guarantees it die completely-- what needs checked first? Just had the tranny rebuilt, and the trans guy can't even road test it!

[pacificcloud]

Originally Posted by ziocles

When it *does* start, it chugs and chokes like it's not getting enough fuel; 'feathering' the accelerator only extends the agony, and steady depression of the pedal only guarantees it die completely-- what needs checked first? Just had the tranny rebuilt, and the trans guy can't even road test it!

I have exactly the same problem on my 89 Aerostar, only it happens randomly after some driving, usually leaving me stuck somewhere. Ironicly I just changed my transmitoin too. I have changed the coil, checked the fuel system presure, but I can't find a problem anywhere. Have you mannaged to fix yours?

[csmarr]

Check the vacuum line that runs to the right side of the transmission. You might have a leak. You might be able to tell if this is the problem by disconnecting the brake booster hose and check the strength of the vacuum. See if opening the hose makes the van run worse.

[teakstone]

Hiya,

To check for a vacuum leak, you can use propane. Just blow a bit of unignited propane where you suspect you have the leak. If the rpms increase the propane is being sucked in and burned inside the cylinders.

It could also be a clogged exhaust system. WHen yo get the engiune to run, put your hand near the exhaust pipe and feel how much pressure there is. Compare it to another vehicle.



For the aerostar, it is more difficult since the engine compartment is cluttered. Also if you pump too much propane it will eventually reach the air intake causing the rpms to increase. This may make you believe you found a a vacuum leak.