hello everyone, im new to this forum and i am seeking some guidance and help on which route go. i have a 99 tahoe , the previous owner showed me reciepts that a goodwrench long block was installed at 86k due to it overheating at a local chevy dealer . i purchased the truck with 112k , at around 130k i started it up one morning with a hard miss i ran codes it had a random cylinder missfire i recently installed new cap , rotor and plugs, i rechecked that stuff first naturally and all checked out ok . due to being our only family vehicle i had no down time for it and drove it for a month as time went on the miss got worse to the point of the entire truck shaking at idle and almost dieing at lights . i removed the valve covers to check and see if the valve train had any obvious issues the rockers on all cylinders would sway side to side about 1/4 inch ...

after talking to a few friends and mechanics , its beleived that the truck has cylinder head issues . where im stuck is do i go and just replace heads and run it or should i rebuild since im that far in to it? and with only having 45k on reman engine im nervous just to do top end build then blow the bottom end . or should i just go with a fresh crate engine ?? if i go crate where are good places to get one ?or if anyone can recommend a good shop where i can take the engine for a rebuild in the phoenix area??. from what i have read online rebuilds cost almost as much as a crate but without any warranty....

this truck will be used as my wifes primary vehicle along with hauling the family everywhere taking trips and the occasional run off road. thanks for any input .

 

Rockers do that. Don't worry about it. Those vortecs are good motors. Its just getting broke in do a leak down test if you think you have head problems. Cheek the oil and water and make sure they aren't mixing. Anyways, I'd bet moneys its a bad I take manifold gasket. That's a very common problem with those. Get a proper diagnosis of what's wrong with it before you spend any money on it!

 

i never thought of intake manifold gaskets, i heard that the lowers are notorious for failing. the coolant level has never dropped and i always change my oil myself every 3500 with mobil 1 oil has come out normally every time and no signs on dipstick. i forgot to mention in earlier post that when i checked the plugs, cyl 2 and 6 had some wetness to them keep in mind that i had at best 2000 miles on those plugs..i will do a leak down on it thanks..

 

Are you sure its not the fuel injection system???

If it has the Spider style Fuel injection, I can almost guarantee you that it needs to be replaced. Very Common on those style engines. But it should be properly diagnosed first.

If you have Spark and compression, I would look at the injection system.

A good mechanic will be able to use a scan tool to do a cylinder de-activation test to determine if its fuel related.

 

X2 ^^^^
Blest plan of action!

 

today i got a compression tester to make sure i have a solid foundation, i am having issues with trying to do a compression test ,i took the duralast battery that was in tahoe and got a new one under warranty ( battery dead , truck has been sitting for almost a year) and i installed new battery in my sierra today and took the old battery from sierra to crank the tahoe over for the compression test however i dont have any power in the truck no interior lights nothing when i turn the key . i took the battery out of my saturn just to rule out a bad battery , same thing no power . i checked fusues under the hood all ok . the tahoe didnt have this issue before i parked it?? any pointers would be appreciated i will jump on it again tomorrow .. just checked fuse panel on driver side dash all fuses good there

if the compression test comes out ok , i dont like the idea of " shotgunning " parts at it but if it is either intake gaskets or the injector spider , would i be better off just dping the lower intake gaskets and the spider at the same time? just to save me from doing either down teh line, both seem to be a common issue from what i have seen...