Mileage not so good

[GeorgeIV]

I have an '01 XLT with a 3.0 liter. My mileage has gone from 21+ to 17.5. I notice a miss/hesitation in the motor once in a while while driving, it feels like I am hitting a small bump in the road. I have replace the wires and plugs and nothing has changed. Suggestions have been a vacuum leak, any other ideas? Thanks!

 

[Wicked_Sludge]

have the codes pulled, just in case something is stored in the PCM. a vacuum leak is a very good possibility.

always start with a full tune-up. air filter, fuel filter, pcv valve.

what brand of plugs did you use?

 

[Ozwynn]

hijack alert......... my minivan is losing power and backfiring under acceleration. I suspect the Cat, but it doesn't smell like rotten eggs. it got no codes either, and nothing stored.

 

[Wicked_Sludge]

fab yourself a backpressure guage, remove an O2 sensor and screw the guage into the hole. IIRC, ford considers 6-7 PSI of backpressure to be "broken".

alternatly, a visual inspection of the cat can sometimes prove its bad (unbolt the cat from the flange and peak inside....blobs of melted substrate or broken/loose ceramic=bad cat).

 

[Ozwynn]

fab yourself a backpressure guage, remove an O2 sensor and screw the guage into the hole. IIRC, ford considers 6-7 PSI of backpressure to be "broken".

alternatly, a visual inspection of the cat can sometimes prove its bad (unbolt the cat from the flange and peak inside....blobs of melted substrate or broken/loose ceramic=bad cat).

if i go through the trouble of getting it out, then i am replacing it. its got 158,000 miles on it. replacing the car anyways but I don't want to pass on a bunch of problems.

 

[Wicked_Sludge]

then replace the cat...what do you want from me?

 

[Ozwynn]

Ideas on what else it might be, I know what the problem is, its a damn chrysler, but i need it to behave until it sells.

 

[Wicked_Sludge]

timing belt or timing chain? backfiring can often be due to jumped time. even compression down both banks? recent tune-up items? healthy fuel pressure?

just gotta start with basic items and make sure everything is within spec.

 

[Ozwynn]

I don't think it jumped time because it only does it under a load. Last tune up was 40,000 miles ago, I pulled the plugs out of the front bank and they still look new. nothing else has changed. not losing any coolant....... i am losing power steering fluid and got no idea where its going. no leaks on the rack and no oil spots in the driveway....... almost looks like its blow by from the reservoir cap. I am never again buying a car with a cross mounted engine. except maybe a Saturn, they are easy to work on.

 

[Wicked_Sludge]

u dunno...my escort is pretty gravy to work on

your only other option is to take it to a shop and have some datastreaming done for you. thats the only way to see what the computer is actually up to.

 

[betomonroy]

And if that doesn't work... Grab a Baseball Bat or am axe... figure the rest.