now what is this thing's deal? i replaced the muffler, starter, battery and starter wiring, alternator, o2 sensor, ect sensor, and replaced intake silencer. the o2 and ect were tripping check engine light so i replaced them. the light still hasn't come back on, and i reset the ecu memory while changing the sensors. now my gas mileage seems to be a little worse! i don't get it. i thought it would get better when i changed the o2. i haven't re-checked the codes, but i plan to even though the light doesn't come on. idles fine, little less hp too of the line, but picks up a bit as the rpms go up. it drives perfect as far as i can tell.. i used to get about 275 to 300 miles out of a tank, now i'm getting more like 200 to 225! what the heck? any ideas out there on what may cause this? i'll post the codes as soon as i get them.
its been about 500-600 miles now and no change... these things get like 25ish mpg right? i'm getting about 17-18. what the hell? for that i might as well have bought that damn hatchback with the 5.0 in it. gas mileage would be about the same... there's gotta be something going on in this thing. still not getting any codes out of the ecu so.... any ideas? maybe fuel injectors? honestly, i don't know fi like i do carbs... tired of it sucking away my paycheck with little payoff. it used to run crappier. if i have all 110 under there now, i might have had 65-70 before. it runs like a champ. definitely can tell that its running better. i know it has a lot of miles, but my girl's old cavalier still got within 5 mpg of what it got from factory after 230,000 miles. i have almost 200,000 on my stang. plan on putting a new motor in there when cash allows, just want it to get 4 cylinder mileage or 6 cylinder horsepower. if i'm payin for the gas, i might as well get to enjoy it, though it is better, i want to smoke tires for the mileage i get. too bad that won't happen with this block...
Hey, Does it seem underpowered at the same time or actually more power??? Is the EGR hooked up and working properly (the exhaust mechanic guy unhooked mine for some odd reason and didn't hook it back up and I was getting TERRIBLE mileage)? Is the O2 sensor the right one? Is your exhaust system flowing freely (a cat could be clogged)?
it has always seemed underpowered, but it is better than it was. i always have to floor the pedal to get up hills around here. even on the eway! i'm pretty sure the o2 sensor is right. it looked a bit different from the one i replaced, but the one i took out looked like it was newer than 15 years old, so i think it was replaced at least once before. i'm pretty sure the cats are ok, but cant just pop em off to check... want to delete them anyway. its giving me a new symptom now too. its trying to die when near idle rpm. i turned it on this morning and it idled fine for about a minute , then it started to slowly lose rpms til it almost died. i goosed the pedal, and it went back to normal for a min. as i pulled to the curb to leave my driveway, it tried to bog down again. it even continued to try to crap out as i pulled out. went away after a sec and didn't show again til this evening. it tried to die on my way to school, but quit as soon as i put it in drive. not sure what it is, but i think i cleaned my egr not too long ago, but i'll check that tonight too. i love this car, but its driving me nuts having to fix something else every week. just want it to run good dammit lol
I assume you done a good tuneup. Only other thing I can think of is a restricted cat. Here is how to test. Just found this method yesterday. Turbo Tek Toys' Tips
If not a direct link scroll on left and go to checking catalic convertor. [Hope I spelled that correct.
i did do a tune up. the only thing i couldn't do was a chassis lube. i have platinum plugs, new wires, new air filter, new belt, new alternator, new starter, new batt, new muffler, synthetic oil, and new wiring from batt to ground, batt to starter relay, and new wires fro relay to starter. could my egr cause my car to die intermittently? i haven't checked that yet. it has a lot of miles, so i guess it could be bad. i'll see what i can do about checking that cat. i still want to just ******* delete it, but money holding me back at the moment.
wonderfulness... 
