2004 base vibe was getting 28 mpg now getting 18 mpg's

[mike48]

Going bonkers here.Have a 04 base vibe with 92,000was getting 28 mpg 2weeks ago now I am down to 18 mpgI cleaned the Mas air,,put new plugs had titanium and replaced with double platinum,Did a vacuum test it holds steady at 25,,do a quick snap at 2500 and it goes up and comes down all in normal range and speed,,no dips or erratic needle readings so according to manual there is no restriction with the readings I am getting off the vacPulled the front oxy sensor today and when shaken it rattled so I replaced it,I showed it to the counterman and he said its bad just looking at it because it was white,,,I just replaced the upstream does anyone think I should change the downstream one also?I believe I am running rich as the tail pipe has black soot in it,and loss of fuel economy.My nieghbor who is a mech plugged his computer in and said all was running normal,,was suppose to take for ride with computer attached but he has been out of town and will not be back till the end of the week.Also I have never got a CEL or any other warning light,the CEL & warning lights were checked to see if they worked and all is working.I have replaced with new the Air Mass Filter and changes oil.this all started about 3 weeks ago on the interstate I was going at about 75-80 for about a 30 minutes and then it seemed to bog down like to much or to little fuel.Pulled over and let sit tried to start it and would start but poop out like not enough gas,,remover the mass air filter and it started,babied it up to 50 mph and it got me home.Seems to run good when I first start it up then about 20 minutes later it starts to run rich again.The only thing I can think of is with 92,000 miles it may be ready for a fuel pump,my thought on thet is how can a fuel pump that might be dying make the engine run rich?Thanks for listening and I hope someone out there has the magic words to fix this,,,,,,,,,,,thanks,,Mike

[lovemyraffe]

That's a tricky one. Did you replace the Mass Air Flow Sensor? I couldn't tell if you changed the MAF or the air filter.

[VforVIBE]

Hello Fellow Florida Viber,Hmmm... I would have said fuel pump, until you said it was running rich... try checking the vacuum line to the fuel pressure regulator for fuel. Is it a lot of black soot?This might not fix it, but it might help it, try Seafoam...

[mike48]

Love,,I changed the mass air flow filter.I cleaned the mass air flow sensor with the spray can made for that sensor.I am considering changing the sensor but at $80.00 I would like some input first.Mike

[mike48]

I did not do that,,where about is it,I have a Corolla manual maybe I should see in there and check it out tonight.Yes I am in Spring HillConsidering the Flat Land down here dropping that much MPG is alot I think.Mike from Florid-ahhhhh~

[northvibe]

clogged or bad cats can cause it... I would have them checked.

[lovemyraffe]

If the MAF is bad, it can cause your car to run rich. This happened to mine a few months back. http://forums.genvibe.com/zerothread?id=39550

[mike48]

Love,,I think I will spring for a mass air sensor tonight as I remember that when I took the mass air filter out that day it started up and ran me good enought to get home.Also I am not getting a code like yours.maybe I should have my battery checked also.Mike

[mike48]

North,,I did a vaccum test and did the snap at 2500 at least and with the response I got the manual said I had no restrictions,also had the wife hit the gas and I put my hand by the tailpipe a nd it seemed to have a good thrust.God I hope its not thecats~!

[star_deceiver]

Check your injectors and other fuel system compenents. A stuck injector or malfunctioning pressure regulator will cause some nice problems.

[mike48]

Problem has been solved.I cleaned the maf with alcohol and a swab.I tested the maf and it showed good.I tested the cats and they had good flow.I replaced the new platinum plugs with new original Iridium plugs.When replacing them I found oil coming from the valve cover gasket inside where the plugs sit and the bolts inside and edges were loose so I tightened them up goodThe first plug on the left had looked like oil going down the threads and the plug looked like it was oil fouled.I put new iridium plug in and used anti sieze and tightened to specs.Fired her up and seemed to run smoother.Took her out today for a 60 mile spin and got approx. 29 mpg in traffic.Mileage was so good I have to go again tomorrow to make suregoing to check her out tomorrow again for a double check on the mileage.She is running great now.Want to thank all who helped a BIG THANKS~!Thanks again,,Mike

[star_deceiver]

Glad it was a simple fix!

[lovemyraffe]

Glad you got it figured out. The battery didn't cause the problems with mine, I think while removing or installing the battery I bumped my intake and that killed my MAF.

[mike48]

Well I went out today and went 93 miles in traffic and I got 31 mpg.So the fix stuck and it is working fine.again thanks to all the shared their knowledge,,Mike