car sluggish - bad mpg

[jwahl16]

2 problems, that are probably related. A/T transmission by the way.

When i floor the pedal the car doesn't go anywhere for like 2-3 seconds and the it "catches" and starts to accelerate faster. When it gets to boost it picks up, but still not as much as it should (maybe because i'm on a 16g with only 10 psi). My car gets beat in the low end by stock family cars.

I also get like 15-16 mpg.

I used to get 10 but i replaced a lot of stuff:

Front o2, fixed boost leak at fpr (17-18 inHG at idle while in drive), changed air filter, and just changed fuel filter (so it's hard to tell if that had much effect).

The o2 sensor brought it up to 14 mpg, then the boost leak and air filter took it up to 15. The fuel filter got it to 16.

The only other thing i could think of is base timing. I read that advanced timing causes it to run poorly. So i guess i should get a timing light?

I think my valve seals are leaking, would they cause bad mpg/ sluggish acceleration?


Thanks a lot, and sorry for the long post.

 

[99gst214]

A thorough boost leak test could tell you if the vavle stem seals are leaking. Do you have a wideband or data logger. Is it running rich? Maybe try another boost leak test. Even with it being an A/T a 16g should still pull by 3500. Does your TC slip at all?

 

[jwahl16]

The 16g does kick in around 3500 the car just doesn't pull like i thought it would. I don't have a wideband or logger. I do believe it is running rich, i occasionally smell gas in the exhaust. And sorry what is tc?

 

[99gst214]

Torque converter! Were all the boost leaks that you found big ones? The little ones are hard to find but still have an impact. This still sounds like your problem.

 

[1995gsx20g]

what kind of exhaust do you have?

 

[jwahl16]

I have a 3" o2 housing with stock exhaust. Would the downsizing hinder power? And i didn't do a full boost leak test as all the air pumps i find don't cut it (i know it's sad). I kind of assumed i was ok since my vac at idle was normal.

I'm planning on replacing all the vac lines with silicon once rre gets some in in a couple weeks. I figured they are probably leaking since they are 15 years old.

Thanks for the replys


EDIT: o and what do you mean by my torque converter slipping? Like not shift properly or something? My transmission seems to operate fine, as does the tachometer, the powers just not reaching the wheels.

 

[Hamp]

Have you changed your ngk spark plugs and plug wires????

 

[1995gsx20g]

I have a 3" o2 housing with stock exhaust. Would the downsizing hinder power? And i didn't do a full boost leak test as all the air pumps i find don't cut it (i know it's sad). I kind of assumed i was ok since my vac at idle was normal.

-the exhaust is most likely the cause for the poor performance.

-on a 15year old car it isn't to hard for the cat to be clogged hurting your mpg, couldn't hurt checking

 

[99gst214]

EDIT: o and what do you mean by my torque converter slipping? Like not shift properly or something? My transmission seems to operate fine, as does the tachometer, the powers just not reaching the wheels.

All transmissions get "Sloppy" over time. The same idea of an old clutch slipping basically. I can tell you that this is not your problem, unless the transmission has like 250,000 miles on it and it had never been serviced!

I would definetly free up that exhaust and use a buddies air compressor to do a better BLT!

 

[jwahl16]

i have new plugs and wire. the plugs have some buildup from my valve seals.

i plan on getting a 3" ebay exhaust in a couple months

and i'll do another boost leak test.

and my car only has 102000 miles so my tranny should be fine


thanks again