Which Way To Go.....problems

[383S-10]

I have 98 GMC Sierra that I recently had the sidetank replaced on the radiator. A few days later it started shudder/vibrate around 40 to 60 mph. I felt it was transmission problem so I took it to my transmission guy who test drove it twice for me in one day. Now this guy eats, sleeps, & drag races Chevys and in his pro opinion he felt it wasnt a trans problem but that it was an engine stumble/miss problem. He told me I needed to go and tune it up & check all the igntion stuff.

So heres what I did:

 

1. Bought new set fo Taylor wires & NGK TR-55 spark plugs; replaced same.

 

2. Pulled off mass air flow & cleaned same.

 

3. Bought new rotor & distributor cap, replaced same.

 

4. Bought new fuel filter, replaced same.

 

5. Had codes checked even though no SES light come on, only code was PO161.

 

6. Pulled & cleaned EGR, the pintel had carbon build up on it and moved down into EGR after

cleaning it moved further and more free than before.

 

Now after all this the truck ran better, more pick up, snappy response, but after 2 days it started shuddering/vibrating between 50 to 55 mph, then later it did it 50 to 60 mph, now its back to 40 to 60 mph.

I took it to another transmission shop & he said it was the torque convertor.......he said after 177,000 miles its time & well over due to rebuild the trans at a cost of $1300 plus dollars.

My original trans guy said after I run through the tune bring it back if it is still acting up.......well I did & he test drove it today. He says that the torque convertor isnt slipping to him & that I have something else wrong. He said he would be glad to rebuild it & replace the torque convertor for a price of $1050 but he really feels that not the problem & that he would taking my money if he did that.

 

So now Im at the cross road of decision making.....tomorrow I plan to have the fuel regulator replaced to cross off one more thing that could be the problem. I did everything on it........I dont fuel pressure gauge to check fuel pressure.... but I replaced the fuel pump a year ago in June 06. Is it easy to replace the fuel regulator on 98 5.7 Vortec? Or do you need any special tools to this? This forum board has helped so much in the past with info for my truck....I just usually do a search & found the answer I needed to fix the problem. But this time Im not so sure what to do about it.

 

Truck info 1998 GMC Sierra

5.7 Vortec

4L60E

177,343 miles

 

P.S. The truck & me tackled the 2005 HOT ROD POWER TOUR leaving N. Alabama to start in Milwaukee, WI

to the finish in Kissimmee, FL & back to N. Alabama.

 

Once again thanks for all the help now & in the past you have given me.