As a mantenience I replace all stated above
Found one of the wires broken with just the fine wire still attached . Guess I found the lost of Mpg and some lack of power
However the rough idle while stopping is still there . Im beating it can be the brake booster

TB was replaced as a preventive after a power reduction happened few months ago which may indicated a bad position sensor

Glad to see the spark plugs were in such a good condition after 50k miles .

 

Those plugs are beat! Look at the gap on them.

For what its worth, my truck ran crap on anything other than AC Delco plugs.

Tim

 

What parts did you go with? I was thinking about doing some aftermarket wires just for ****s one day.

 

Same here.....

Not sure what wires Miami used. When I did mine I went with Taylor cable 79205 409 wires and AC Delco 41-110 Iridium plugs.

Links to both on Amazon where I bought them....

Wires - Plugs -

 

Awesome, I'd had both those wires and plugs sitting in my Amazon cart for years lol. Maybe I'll pull the trigger, looking for something to do to my rig lol.

 

I used these same wires when I replaced mine a couple of years ago and I haven't had any problems with them.

 

I put in Taylor wires and NGk plugs in both my trucks. No issues at all.

 

I Used ac delco . Gave me a good results for the last 60k miles
The Tb was any overkill . I could have cleaned the old one but a few months ago got a suddenly power reduce engine while driving on speedway . Dealer told me it was the Tb position sensor .

Still got to figure out the rough idle while stopping
Is there a idle valve to replace if so where is it and how to
Thx

 

No specific idle valve - that is actually a function of the throttle body by the tiny bit that it keeps the butterfly open. The idle speed can be electronically adjusted with a tune but that does not help with rough idle.

Rough idle could be a number of things. You have taken care of the obvious with the plugs, wires, and throttle body. My next guess would be a vacuum leak. Unfortunately that "could" be the intake manifold gaskets. I seem to remember you had the intake off at some point. Did you have any rough idle before that? Once semi-common thing on the GM truck intakes is when re-installing a bit of the wire for the knock sensors can get over to the side and get pinched in the gasket. Or if re-using the original gaskets they are just too worn with flat spots and need new ones, one might have gotten a nick in it, etc.

Other potential leak or issues could be the little fuel pressure regulator on the drivers side of the intake which has a vacuum line to it, or the PCV air tube, or possibly some unused nipple on the intake manifold itself got knocked and cracked open slightly. One way to check for leaks is using carb cleaner but its potentially dangerous if you accidentally get some on the hot exhaust (just keep a fire extinguisher handy) but being careful it really is not that bad. You can spray little shots of carb cleaner around all those areas on the intake while the truck is running. If there is a leak the engine sound and idle will noticeably change if it sucks some carb cleaner in wherever the leak is.

 

@mixmansc ... thank you for the input.
Yes I think The intake was removed when the valley pan was replaced
Now I'm not sure if it matters but I checked the vacuum and is steady @19 . Also working as supposed.

I will check the vacuum lines, fuel pressure regulator and pcv
I saw a video which use propane gas instead carb cleanner . They claim is safer .