Crappy fuel econ/sugglish power...

[bcowie]

Do you have another Tb you can try?

[Cool_Steve]

No. I have been meaning to get to the wreckers but I haven't had the time.

[Mazda_Powered]

I can get you an auto b8 throttle body Steve, want one? $25-30 shipped?

[Cool_Steve]

Mom's Protege just rolled over 200,000kms, still runs better than mine at 152k. I don't get it. Even hitting the gas in reverse out of the driveway I can feel her's has better response. It all boils down to me having to push my pedal farther than her's to get that response. When done in her car, it kicks up and goes. In mine, its a split second slower on the draw and just lacks punch. At this rate the only thing this problem is good for is keeping me free of speeding tickets. I still wonder if it's the transmission.

And while I've gotten horrible economy in the winter, I just recently got a respectable 40.3MPG/7.1 liters per 100km through several highway trips on my last tank. The highest I reached since I have been keeping track of my economy was 38.5MPG last year. With this tied with the fact I blew low and clean on drive clean this year, I can't see it being an o2 sensor. My TPS CEL wasn't really a 'true' trigger as I had forgotten I had unplugged it in late 2010 and never cleared the code, so it was still there when I unplugged the o2 wire earlier this year and both codes flashed. At any rate, the TPS is in such a crappy spot to take out. I tried to grab two from the auto wreckers and stripped the screws. I doubt I'll be able to take mine out.

Maybe something needs oiling/greasing? When moving the throttle cable in the engine bay with my hand, mine seems to have a bit more resistance than her's. I guess this leads to my pedal not being as responsive as her's? I keep forgetting to test the TPS and July was terrible here to work outside on anything. Other than this issue that has been dogging me for several years now, I haven't had any other issues as of late.

[MazdaNoob]

give up and come sell me the shell

[MADMIKE]

Maybe something needs oiling/greasing? When moving the throttle cable in the engine bay with my hand, mine seems to have a bit more resistance than her's. I guess this leads to my pedal not being as responsive as her's? I keep forgetting to test the TPS and July was terrible here to work outside on anything. Other than this issue that has been dogging me for several years now, I haven't had any other issues as of late.

Possibly a worn out throttle shaft. This would cause the sticking feel and also cause an air leak, which would cause your car to run lean, and possibly give an incorrect signal from the TPS for a given throttle angle.

Test that TPS. Look for any corroded or damaged wiring, make sure all your grounds are good. Make sure the rotor and cap are free of grease and oil inside and out.

As for the ATF trick, dumping in a quart into the tank is similar to dumping seafoam into the gas. You can also try an engine flush with ATF. Get the engine good and warm, drain your oil, replace the plug, fill up the oil pan with ATF, start the engine and let it idle for 5-10mins. DO NOT DRIVE IT!.
Pull oil plug and watch all sorts of ****e and sludge pour out. Replace filter, refill with oil. This is great for removing sludge from lifters.

[Cool_Steve]

Mom took a trip up north in her Protege recently, this is how much gas she had left after 653.2km/408.2mi. She ended up getting 763.4km/477.1mi out of that tank. However my economy numbers are wrong because when she filled up full tank she had a now fixed leaky filler neck, and the pump didn't stop like it usually does when you pump gas and get close to the top. She crammed 51.559L/11.34gal in there and surprisingly it didn't spill everywhere. It calculates out to only 42.1MPG. Had she pumped the more usual amount of 40-45L its probable she averaged 50MPG. I'd say that's very good economy for an old four banger built on old technology, auto with 200kms on the clock. Somehow I can't touch that. She still has the original o2 sensor, fuel filter and spark plugs wires as well.

When I get a free moment I will check the TPS.

[MADMIKE]

653.2km/408.2mi. 51.559L/11.34gal in there and surprisingly it didn't spill everywhere. It calculates out to only 42.1MPG.

Even when converting that to US gallons thats still ~36MPG. At best I've only been getting 26-28MPG. I'm not sure if its the oxygenated gas or what the hell. This thing used to easily get 30-31mpg driving it like was stolen. BAH!
I'll have to look at the damn TPS and maybe give everything a once over. Bugger.

[MADMIKE]

Just filled up last night. 26MPG, I think I'll replace the O2 maybe its become lazy on me.
FWIW I went to www.fueleconomy.gov according to their website the original sticker MPG was 24/31, 27 combined. New rating is 21/29, 24 combined. I think I'll try to seafoam the bugger, may even have the fuel injectors checked for spray and flow.

[cablemirc]

be careful with that seafoam, i actually made a nice cloud on mission bay in san diego with it, so much so the fire department was circling looking for the fire, but i had hightailed it out of there already. yeah, that much smoke.. either go somewhere deserted, and i mean really deserted, or pick a really windy night. and don't forget you'll need to change your plugs immediately after. lessons learned!

[MADMIKE]

I know our cars have a fuel pickup issue when the tank gets low, usually shows its ugly head when you are below half tank and taking corners, or if you are down to the 1/4 mark and are parked on a hill. She sometimes does not want to fire up right away.

Picked up a 16oz bottle of Seafoam. "1oz Seafoam per gallon of fuel". With my awesome math skills on the spot I divided the can into 4 sections. ~12oz for the tank, and ~4 oz for the crankcase.
Pulled into the same gas station I always go to, same pump, same fuel, same nozzle. This time there was still ~1/2 tank full.

Topped off and put in 5.25 gallons, tripometer showed 185miles. That's 35MPG. A 9MPG leap from 26MPG? There is something seriously fubared going on.

Is the fuel starvation/pickup issue THAT much of an issue on some of our cars? I'm going to assume there must be some component that is no longer submerged or is not properly working at half tank. Where does the pump sit exactly in the tank?

I've been meaning to pull the back seat and check on the sender/float/sock/pump assembly. I dumped Seafoam into the tank and crankcase. When it gets to half tank again, I'll pull the sender unit out before refilling.

[MazdaNoob]

the fuel pickup issue is usualy for cars that have had the gas tank replaced with non-oem tanks. the oem tanks have baffles in them to keep fuel @ the pickup when cornering . also might be an age of the sock filter issue as well. Thirdly condensation buildup and sludge over they years can add a significant amount of "unburnable" crap that sits low in the tank . cornering hard with room to move may bring that to the pickup as well. The oem pro tank has a drain plug bottom center of the tank (as the easy way to tell if it's been replaced)

[MADMIKE]

I'm fairly sure the tank is original. It does have the drain plug, I have contemplated draining the tank, filling it with a gallon of ATF let it sit for a day and then drain it again. I've done the ATF flush on my engines, and that has always been foul. The gloppy mess that pours out is rank, although I do not know if ATF alone would be able to work as well as a cleaner without some heat. There is a rad shop local, and I wouldn't mind doing a boil and recoat, its just the down time I think would suck.

[gofanu]

I'm fairly sure the tank is original. It does have the drain plug, I have contemplated draining the tank, filling it with a gallon of ATF let it sit for a day and then drain it again. I've done the ATF flush on my engines, and that has always been foul. The gloppy mess that pours out is rank, although I do not know if ATF alone would be able to work as well as a cleaner without some heat. There is a rad shop local, and I wouldn't mind doing a boil and recoat, its just the down time I think would suck.

Takes a whole ten minutes to pull the sender/pump and look in. As long as it's not tippy top full, no problem. I've had several out here in PA, and found only a couple tablespoons of water, no rust or other crap. Sucked the water up with a siphon hose.

The pump is in the middle, in a baffle box. If you have sticky tires and really throw it into a tight turn and stand on it, it will cough even at near half full.

If you are relying on the gauge for fuel mileage calcs, you are a hopeless idjut! I find that all the gauges are different, and you need to figure out what yours does, and still consider that it is probably lying. They are especially useless in midrange. Mine all read over full for 75-120 miles, depending on which car, then it's "some gas" for about 200 miles. "Some gas" is different depending on whether you just started it, or just got home, or went around a corner or up/down a hill lately. The good news is that the last 100 miles and "E" seems to be consistent on each car, but wildly different between cars. One means empty, one has about 1.5gal, and one has about 3 gallons. As long as I don't forget which one I'm in, I'm good.

ProDx driven by madman usually 31mpg with 195/60/14, 323 w/185/60/14 32mpg crazy/ 38 leisurely country driving. Both better on interstate at posted speeds, and better yet when you could still find no ethanol gas. 323 auto was same on the highway when locked up, but sucked in town - 25/26mpg.

FRM