Home Forums Gear Hunting Trucks and Four-Wheel Drives 1999 Suburban mechanical puzzler

That's one of the first things I'd check/change. Some of these other guys are giving you some free advice, but may not even own a '99 suburban...

Find a good mechanic....and save yourself a bunch of guessing and buying and replacing parts that don't need it...all the things listed could be the cause of the problem..I have a 93 with 5.7 and a 99 with 7.4 both have done similar with a different thing that were wrong...
The 160k mileage range I had to replace the whole distributer one time and fuel injectors and a fuel pump...all acted similar..
If it ain't broke don't fix it..

The day in the life of a GM owner. LOL

Have fun boys!

Just for an update, started fine today and idled okay for ten minutes or so. Again had no time to do more.

tz: The reason I don't have a "good mechanic" as rrfc suggested, is I've had so few problems with Chevy. That said, I have nothing against Ford.

The 93 Chevy I have just fooled 300 k. Original motor...and it round like a top... The reason I suggest a good.....mechanic...I had a lot of little stuff go haywire at150-180 k it got real frustrating to just throw parts at it..
My son has an 87 that would do similar to yours...a 99 model with 160 k probably sits a lot his had rust build up in the tank,from ethanol...and would plug the screen on the fuel pump....put in a new tank from mc truck and problem solved...
By the way you couldn't give me another ford....lol

On my 95, I wrecked a coil by letting the cap and rotor go too long. It would start OK when it was cold, but not warm.

My wife's 99 suburban has been rock solid for us. Well except for the alternators (it's gone thru about 5 in the last 10 years), the distributor cap conundrum and the reaction sun shell in the transmission. This is a very common problem with this year of suburban/GM products that use the 4L60E, but simple enough to replace. My 2004 GMC, on the other hand, has been kind of troublesome. New tranny at 110,000 miles, transfer case at 139,000, rear end at 125,000, front differential rebuilt at 115,000. The LS1 5.3 is damn good and doesn't use or leak a drop of oil. If I didn't know how to work on cars, all these fixes would have bankrupted me in the last couple years..

Since there is so much experience with distributor caps, does spending more money for one give you a better chance of avoiding problems down the road, so to speak? Looks like you can spend anywhere from $35 to $60 for one. It it makes a difference, paying a little more isn't that big a deal.

Like I said before, ONLY buy a factory OEM replacement (AC Delco). Many guys have also had excellent success with the Accel brand aftermarket cap. This is the one I ended up buying after the $55.00 one from the local automotive parts house didn't cut the mustard...

BSA has som good advice ...my old 93 has always got ac delco parts. They cost more but when it's fixed its fixed..
It's on its second starter...most Chevys eat parts store starters at a rate of 1 or 2 a year...ac delco starters cost double but usually last 10 years..

I spent the money on Delco. The off brand that I tried corroded faster.

I had so many issues with my 04 that I don't think I could stomach another. I hate to say it but this Ram I have has gone the longest so far without repair of any vehicle I've had other than my 06 Tundra.

I have a giant pile of crow to eat on that deal.

The ford gods are going to be so pizzed at you...

You mean the Tundra gave good service?

Here's a potential solution to your problem.

---------------------------

"GM Vortec V-6 & V-8 engine Application Alert
1997 and newer GM vehicles equipped with “Vortec” type engines may experience misfires
and hesitation due to moisture accumulation inside the distributor cap and a general lack of
airflow inside distributor. GM TSB #03-06-04-041A & #05500 involves 2001-2003 vehicles
however, the condition may occur in earlier and later vehicles. Whenever servicing a Vortec
distributor the following should be performed:
1) Inspect and clear 2 distributor vents on early models. On later models with vent screens, the 2
screens should be removed.
2) Check for coolant leaks near distributor from heater hoses or other sources of potential leakage.
3) Inspect PVC system and change engine oil on schedule. Moisture in pressurized crankcase vapors
can be forced up distributor shaft and contaminate the cap and rotor causing internal arcing and
corrosion.
4) If A/C equipped, insulate accumulator line near distributor base. A 9 inch long piece of foam having
an internal diameter of 1.25 inches and .25 inch wall thickness is recommended."

----------------------------

If the vents in dist are clogged it can cause corrosion and arcing (erosion) due to moisture.

There's a consensus among those "in the know" that AC Delco ignition parts are the only way to go. Aftermarket dist caps and rotors are notorious for eroding faster than OEM. I bought a Napa Gold cap and rotor for my 98 chevy and it looked like crap after 30k. The original cap and rotor looked better at 100k than the Napa parts.

It's also possible that there could be other weak ignition components that might cause problems with excessive erosion.

I'll add this too. The best place on the internet for info on chevy trucks is fullsizechevy.com. It's great forum with many knowledgeable folks that are happy to help.

It's just like the fire.

Good advice fish head..

I forgot to mention the vortex plastic intake manafold....has yours been changed? More than likely it has...but there was a problem with all of them... By 99 they may have been coming out of the factory fixed...
The 97-98 s had the problem for sure but not sure about the 99s

FWIW,

The Vortec series of engines (96 to 99 - 4.3, 5.0, 5.7) have a plastic upper intake manifold but the lower portion is aluminium. The problem is with the intake manifold gasket (between the heads and IM), not the manifold(s) themselves. The OEM gasket was a defective design and they all have or will eventually fail.

Fel-Pro came out with a new IM gasket that cures the problem once and for all.

This is good advice. Expansion and contraction of a plastic intake can be a reason for vacuum leaks. Also could be the reason it starts ok cold then gives problems when it warms up. When running, try to spray some carb cleaner along the intake gaskets and see if the idle changes any. If it does, you have a bad gasket as mentioned above.

Also a firm believer in going back with AC Delco on the cap and rotor.


Clyde.

The mechanic, who is a pretty good mechanic, says it was the coolant temperature sensor. It has been replaced. Hard for me to believe, but we'll see.

He also noted a leaking intake manifold.

And front axle seals seeping.

Quoted a repair price that's nearly half of book value.

If those are fixed it's a pretty solid truck again, even if it is 16 years old.

As I said, we'll see.