Transmission Issue?

[dturner8]

Hey guys..Im finding this site very helpful it diagnosing problems with my 97 GMC Z71 w/ 193K miles. I thought I was post this and see what it could be.

 

This truck was my first automatic trans...so i didnt know about the filter etc....that was a $1400 mistake So, I got my trans replaced. and have kept it pretty maintained.

 

Last summer my truck started to feel like it almost running out of gas...at about 30-40 mph, it felt like it was dying...but then i looked at my tach and the needle is jumping up (not much...almost like it is reving up about 200-300 rpms) when it feels like it is dying. This has continued to where it does it unless im giving it gas in a steady acceleration or at anytime at a constant speed under 55 mph.

 

I have:

 

1) changed out all 4 O2 sensors

2) had the top hat removed and the back 4 fuel injectors replaced (i was told by my mechanic that the front 4 appeared fine and at the cost of them...he wouldnt replace them unless he had to. I do trust the guy)

3) fuel pump failed - replaced the fule pump and replaced the fuel filter at the same time

4) cleaned the throttle body good, got all the funk out.

5) replaced fuel filter again.

6) had the trans serviced again.

7) I run premium gas and a bottle of gum-out thru the fuel system every 3k-5k miles.

 

I get pretty decent mpg...(been keeping track for the last 100K, and im getting 15.622mpg - K&N filter and flowmaster pipes, Im pretty happy with the mpg) so me gut feeling is it is something to do with the powertrain itself.

 

Now im stuck...not sure which way to turn. Does the automatic have a clutch that could be going out? Could it be a torque converter? Throttle Position Sensor, Fuel Pressure regulator? I have read thru this forum...but nothing quite matches the problem im having.

 

 

Id appreciate any thoughts. Other than the driver's seat not keeping the lumbar inflated...im still very happy with it.

 

Thanks for your help

 

Dale

[Chanks7]

When was the last time you replaced your spark plugs or wires?

[dturner8]

Im sorry...I left that I swapped out the plugs.....

 

 

But that is the one thing i havent done is the wires. I have done them before, but not the last time I swapped out the plugs.

 

I would think that my mpg would diminish if i was having problems wiht a plug or wire...but then again..who knows.

 

I have struggled to find any info on the web about it...I guess Ill try the wires (and probably the plugs again) this weekend.

 

Dale

[dturner8]

Replaced the wires and plugs this weekend....

 

Still having the issue. Do you know if these trucks have a throttle sesor? could it be failing? Do you think it could be the fuel pressure regulator?

 

Im at the point where I dont know where to turn.

 

Thanks