Engine is loping sometimes

[Samurai0]

Hi,

I've noticed something recently where the engine lopes a bit, or may even seem to want to konk-out when shifting between the D & R shift positions (like in a 3-point turn).

Anybody run into this?

[fredjacksonsan]

Yeah, I have an 87 with the same thing happening, as well as dying at stop lights. It was idling really slow, so turned up idle screw a bit and that seemed to help. I'm also looking for a vacuum leak somewhere.

[Samurai0]

Originally Posted by fredjacksonsan

Yeah, I have an 87 with the same thing happening, as well as dying at stop lights. It was idling really slow, so turned up idle screw a bit and that seemed to help. I'm also looking for a vacuum leak somewhere.

Hmmmm.
Idle screw? Where's the idle screw?
Do you have EFI?

Hmmm.
Yup. It's like the idle is tooooo lowww.
I'm gonna check out the airflow sensor too, because I believe the thing
is using way to much gas.

Anyway's I can't wait until it's 25yo In New York, cars at 25 years have no emissions requirements anymore.
I can't wait to swap out the electronic emissions $hit for a 4 barrel holley and racing edelbrock manifold.

[fredjacksonsan]

Yeah, it's a 5.0 with EFI; looking from the front of the vehicle, the idle screw is just to the left of the air filter box, and just below the aluminum intake. On mine it's behind a couple of sensor wires. Clockwise will increase the idle.

I'm sure there are some sensors that are dying, or maybe the cumulative effect of age on all that electronic stuff. That's why you'll see original 60's cars, but hardly any early FI cars...all the electronics die and you can't fix it without selling your house.

[peterand]

I had trouble with mileage, loss of power, stalling. I had it into the garage a few times and spent a couple grand. It ended up being the Cadilatic Convertors were partly plugged. Blew them out and all was better. My mileage went from 18Mpg to 32Mpg.

[Samurai0]

How'd you "unplug" them? You must've had to have them cut down, and welded back in.

[fredjacksonsan]

Wow, blew out the cats and went up to 32mpg? This is an old merc grand marquis with the 5.0? I think I'll have to do the same!!!

I know that some folks just take a 1" drill bit and put a hole through the middle to keep some of the pollution control ability; I've also heard of some that just took out all the material in the converters, their veh still passed emissions.

[cobradude360]

ok on the 4.6 leter v8s in the merc if u fallow the air box all the way to the intake theres the lever were u can control the intakeand if u look at it theres a little black stud like thingy take a pair of pliers and make sure the engine is running and adjust it to were ever u want another thing i found works to control the idel is clean the inside of the throttle body then adjust the throttle positioning screw good luck

[Samurai0]

I think......If you gut the CAT's then you're making an 'expansion chamber' where the hot gasses could be given a bit more time to "burn".

I've seen this on some small cars, but the CAT's on my car are 3-way (air injected), to force extra combustion.

Hmmmm.