Korishan

Ugh, I guess I'll be changing the fluids today or tomorrow, then. *sigh* all that previous work for nada. But, if it gets me back at 22mpg, i'm happy. even 20 would be fine. Gas is too damn expensive to be gettin 12mpg.

And, no, the previous owner didn't take anything out of the car. I knew what was in there b4 I let him borrow it for a little bit, and the car ran perfect for 2 tanks after I got it back. It wasn't until I put the sea foam and new fluids/air filter in did it start actin wierd.

Fun fun fun.

Thnx for the input, much appreciated.

sweet99

Well then it's narrowed down to the seafoam. Changing the fluids will simply protect the tranny and engine.
More importaNTLY IS TO CHange the plugs. I am happy with my NGK platinums at $3. each. Read the sticky about 4.6 owners at the beginning of this forum. It has directions and all you need to remove on the passenger side is the air intake tube to the TB and maybe a couple of hoses that attach to it. Are you sure thAT THE SERVICE ENGINE SOON light works in the dash? Turn the key to the on position and it should light up, I think it's on the left side. Also with that bad of a drop you should be smoking black out of your exhaust and it should be covered in soot, plugs also. If you can post a pic of a plug thAT WOULD HELP.
wHEN YOU CHANGED THE FILTER IT'S POSSIBLE THE AIR INTAKE SENSOR COULD HAVE FALLEN OUT OR GOTTEN DAMAGED. iT'S ON TOP OF THE INLET TUBE NEAR THE AIR CAN. Excuse these caps!
You need to backtrack everything you did and be sure everything is attached, no hoses off.
Did you drop the MAF by chance?
How does the motor idle, it should be really bad if you have lost that much. How about if you rev it in neutral to say 3000 rpm's and hold it there, it must be misfiring, yes?
Something got knocked loose or that seafoam messed up the injectors. Read about the plug changing. It's easy and you need not remove anything but the air tube.
A shop would have the capability to run a diagnostic check and I would have that done for sure so you don't keep throwing money at it. Does it still have the cats? If that's been asked I forgot.
Like I said backtrack what you did and see if you can find something not attached where it should be. Good luck, Mark
PS: the lack of a service engine light is odd.

ackuric

did your right foot gain a few lbs?

happens to the best of us

Brute03

first thing i would do is get rid of those quad-tip plugs, the 4.6 usually runs really crappy with those plugs

sweet99

Give the guy some slack. He lost 10MPG somewhwre and help is what he needs. By the way the mods you have listed as coming up would get you a SC so why go for the ponies when you can have the Clysdales? Mark

qbuswell

Puttting that heavy of motor oil in hurt you. USe 5w20 like the car recommends or if you live where it is hotter than hell all the time use 5w30........and check the fuel filter.

ackuric

ive used 10w-30, no drops as for as mpg's. if so, 1-2.

To lose 10 mpg, would take a combination of things, or one thing gone horribly wrong. i dont think, in anyway shape or form, will seafoam cause his drop, nor the filter. bosch 4+ are no good, and can cause all sorts of problems, so indeed, i would replace those.

going around town giving your stang some peddle, will yeild anywhere from 8-14 mpg, but thats beating on it, haha. could be a combination of a few things he did, his driving, weather, the gas he filled up with. i mentioned 'lead foot' because it is a lot more likely to cause a loss of 10mpg, before any of the other things he has recently done. and if so, he would be here complaining about his car running horribly as well. havent seen him mention that...i could be wrong though

bigedog8

do u have the 20w-50 oil in your motor? im confused. I think all the mod motors are supposed to have 5w-20 (correct me if im wrong someone). i was just confused by how u worded everything. should have a thinner oil.....

Korishan

Yeah, all the dash lights work, well, most of them. When I turn the headlights on, no normal dash lights come on, except bright when I put brights on. The service engine, theft, airbag, seatbelt, all those lights come on when i turn the ignition on. I haven't seen the service engine light come on at all except during first ignition.

I'll see if I can get a picture tomorrow morning before I go to work to show what the plugs look like. Thank goodness for camera phones

As far as I can tell, I didn't knock any hoses loose. I checked the connections, electrical and vaccuum to make sure, they all seem to be in place. Also, aired up the tires. They were actually down about 20lbs. And my car got towed last night so I had to get it back today (which was a big pain in the ***). When I got back and it sat for a few hours, I noticed my driver rear tire was down to only 10lbs. Bastards better not of damaged my tires. Grrr

When I installed the new air filter, all I did was unclip the MAF & bend the air intake assembly back a little to change filters. I didn't unbolt or remove anything else. So I know there's no dropping damage done to the MAF. I haven't noticed any black smoke out the tail, I'll check that tomorrow too. Also I'll smell for richness in the exhaust. I won't breath it too long

The cat's are still there. I haven't removed those. As far as idling goes, when I first start up in the morning, about 900rpms. Once it's warmed up, in neutral it's about 750rpms, and in drive with foot on break, it's about 650rpms. Sometimes when sitting idle I'll watch the amp meter and the rpms will be at like 700rpms or so, and the gauge will go from almost straight up to about 1/3 to the left (going down), then it'll return to normal. Sometimes it repeats this a few times. I've noticed when driving and the rpms are over 1k, I'll feel a very very slight hesitation and I've noticed the amp meter drop about 1/4" and return to normal. I guess I could run some wires inside from the battery and plug a digital meter to it so I can monitor everything a bit more precisely. The cig lighter goes through fuses and such which would alter the overall reading, wouldn't it?

If the sea foam did some damage, what can I do to re-clean my injectors and such? Should I just take some other injector cleaner (like Lucas, which I've used in other vehicles b4 w/ success & no problems), or use something else. At this point, I will spend a little extra money than normal to get my pony back in shape. And, is there any way to really look at the O2 sensors or clean them or something?

And yeah, I do have the heavier oil in it. I will change to 10W30 or 5W20 probly Tue when I have my day off. But I doubt the thicker oil is causing "that" much resistance. Now, if I had gear oil in there, then yeah
Also, I have looked, probly over looked it, but where is the fuel filter? Wouldn't it be under the passenger door side of the car? I looked there and didn't see it. *ponders*

Thanks for the info, you all a great help. Quick replies, too

Korishan

Ok, here's the pic of the spark plug. Not very good, but they are blackish. You can't see in the pic, but there are lighter areas where the sparks were firing around the pit to the points.




I put Bosch Platinum 2's in. Runs pretty good. Idles in part at about 750. I haven't noticed any wierd drops in the amp meter yet. Revs up nice, too. Also changed out the fuel filter.