99 Tahoe 5.7 is driving me NUTS!

[Stlrboo]

I've had this Tahoe since it was new.. 2 door LS! Have never changed from stock, except for a set of wheels/rims that keep my speedo running correctly!

Whenever this truck sits for more than a few days in humid or cold conditions, it won't start, makes clunky noises and tries to turn over, but NO luck.. My Mechanic has done everthing that could possibly be replaced, and I'll be damned if I'll have it towed to his garage again, and have a rotor/cap put on it AGAIN! WHY does this keep happening??

I have babied this truck.. 77,000 miles, and the oil has been changed every 3000, and I'm running Pennzoil Platinum 10-30W.. Fuel filter/pump, plugs, wires cap/rotor, battery etc, have been replaced in the last year! Intake manifold gaskets were replaced two years ago.. Oil is clean and smells right..

Once it does start, (when the weather warms up) it idles smoothly, but on acceleration, has a 'miss'.. This thing is a 4WD Tahoe.. I have to leave it in the garage in the winter and drive the wife's Mazda (ACKKK)..

Please help...
ps: Is not setting a code.. Only code it has ever set is a 'misfire'..

 

[1999HOE]

Tahoeyukonforums

 

[olpir8]

1999 Tahoe Misfire

Had the same issue for over a year... The engine finally desintegrated and I put a new engine in at 130,000.... It still had a misfire... After taking it back to the mechanic 3 times and him doing nothing but replacing wires, plugs and rotor caps I decided to fix it myself...
It had cylinder #3 misfiring intermittently.... I decided to pull the distributor...
The two teeth were broken and the rest were sharpened to a knife blade point.... I spent $90.00 on a new distributor from the web and replaced it myself.... It now runs like a stripped snake.... For the life of me I can't figure out why my mechanic would put a totally worn out distributor on a new engine..... go figure... If you want it done right after $400. do it yourself...
Hope this helps... Olpir8