bad gas milage

[bscoffey]

i have a 2001 astro with 135,00 miles and can only get around 14 or 15 mpg. this is a 2wd van with 3.42 gears. I tuned it up changed all the fluids & all the filters. I even replace the spider assembly with the updated version.still bad mileage.I used to work at pepsi cola and drove a 1995 and it got over 20 mpg. I realize the intakes are different and the injectors are also different. but that shouldn't account for the excessive fuel consumption. I have also done a fuel pressure test and mine leaks down a little after the pump quits running. like 2 or 3 pounds a sec. I also noticed a rougher idle after the spider assembly was installed (sometimes). i dont have any codes either. I thought it may be a lazy o2 sensor but i really dont want to start throwing parts at it to try to fix a simple problem. any help would be greatly appreciated.

[Blue Bowtie]

What is the percentage of city driving versus highway driving at a sustained speed?

[bscoffey]

city mpg is 12 to 14 , hwy is 15 or 16 mpg. i debated on getting a awd but opted for the 2wd for the "better" fuel economy.big mistake. i noticed a little hesitation yesterday ,only while pulling away not on a steady run.

[Blue Bowtie]

My AWD w/3.73 gears gets right at 20 MPG on the highway if driven "normally" and more like 17 if loaded w/ 6 people and their gear at 75 MPH. I'd consistently get 17 with just two of us pulling a boat at 75 MPH for 360 miles.

The fuel pressure leakdown may indicate a leaking injector or FPR, or even a leaking line set in the plenum. Any of those could be hurting mileage, and potentially be causing the poor idle. Eliminate all the easy things, like ignition, vacuum leaks, and compression, then you may have to look into the injection system again.

[bscoffey]

do you think that the new spider i installed might have a problem? I just replaced the o2 sensors (all 3) it seems to doing a little better. Still has a simi-rough idle after it warms up. What about the transmission & tourqe converter? seems like at take-off its not so responsive,like its straining only on a hill or slight incline. At wits end,thinking of selling it and buying a toyota truck. thanks for the reply

[boatbuster]

I have an 02 AWD Astro and get around 18 to 20 on the highway, she drops quite a bit if I tow with it. I also felt like I was losing power and it turned out to be the cat converter that was clogging. I also changed the distributor and it helped bring the power back up. My distributor gear was pretty badly stripped. This also helped with the idle issue.

Might not be your issue, but worth looking into.

[bscoffey]

boatbuster,
How did you determine the converter was stoped up? did it sound different? i did pull the distributor and there was some play in the shaft, thought it was normal. also how much did you have to spend on parts?

[boatbuster]

We did not even think of the cat converter until she died on me. When she finally did die on me, I had to get the van towed home. After days of changing everything, I was about to get the fuel pump replaced thinking there was nothing else and someone told me to pull an O2 sensor and try to start it, she started but ran very rough, that is when we realized that the distributor gear was also worn. If you have play in your distributor bushings, then you might also have a worn gear, those are sacrificial gears and will wear before the cam gear. I got my complete AC Delco distributor (rebuilt with a 1 year warranty) from Napa for around $150 or so, I would have to pull out the invoice. Might be a good idea to pull the distributor and look at the gear.

As for the cat converter, you mentionned replacing the spider, if you have too much fuel going through the engine it will clog up the converter. You also said you were using a lot of fuel, this could clog up the converter. On mine, the timing would jump up to 19 degrees due to the bad distributor gear. We replaced the gear to start and it worked for about a month and finally wore again, so I replaced the distributor. The cat converter ended up costing me almost $1000, installed. The clogged converter acted like I had a fuel pump problem, she would run fine and all of a sudden shut down like I ran out of gas. I would wait about 20 minutes and she started back up as if nothing happenned. The van was also very sluggish.