: 350 Vortec

07-25-05, 11:00 PM
I recently bought a 99 Escalade w/ 44k miles on it. I had a 95 Silverado w/ a 350 in before and it way more power. If I try to accelerate in the Escaladeand the rpm's hit 3000 the engine will shut down until I back off the gas. It is stopping me from letting it out. I cleaned the throttle body and ran a gas additive. Does anyone know if this is common? The 350 is supposed to be fine on 87 octane, so I assumed that is was something else. Any info?

07-25-05, 11:30 PM
just remember the escalade weighs alot more than the silvy you had.

07-25-05, 11:48 PM
Good point. Any ideas about why the engine would kill itself at 3000 rpm's? I puzzled.

07-26-05, 01:06 AM
You've covered fuel and air...all that's left to check is spark. Bad plug or wire? Perhaps a dirty fuel filter, or the fuel pump may be on its way out.

The bad thing about power loss is it's a trial and error process because of the numerous amount of things that could be going on. First check for a plugged fuel filter, it's a cheap fix. Next you may want a fresh set of plugs and wires. If after plugs and wires you're not fixed you may need a new coil pack. You may also have cloggeded catalytic converters, or a bad 02 sensor. Good luck, let us know what it is that's ailing your ride.

07-26-05, 08:10 AM
As said above I would do a tune-up and change the fuel filter, that should help take care of your problem

07-26-05, 09:52 AM
I will try that. Thanks for the info.

07-26-05, 03:44 PM
I am not very familiar with the Vortec .....yet. But, is there a knock sensor that could pull engine timing in the event of pre-ignition/detonation? My LS1 engine will do that if lower octane fuel is used--especially under hard acceleration. If your timing is retarded by the ECU, it would cause a noticable loss of power. Try a tank of higher octane gas and see if the problem persists. Just a thought.

07-26-05, 05:50 PM
My guess is fuel filter. Also get a can of seafoam and put in tank there are fuel injectors in the intake manifold that might be partially clogged. Seafoam is a brand of fuel injector cleaner if you are not familiar with it NAPA usually has it.

07-27-05, 09:56 AM
A friend of mine with a 99 had the same type problem and has been running higher octane gas even though it is supposed to be fine on 87. I will try that also and see if it makes a difference.

07-27-05, 06:46 PM
As engines get more miles on them, their requirement for higher octane can increase. This is mostly due to carbon deposits that build up over time. During combustion, the carbon stays hot so hot through the combustion cycle that it will start uncontrolled fuel burning before the ignition spark is fired, pre-ignition. Pre-ignition is an uncontrolled burn, not effecient, polluting, and power robbing. It ia also not good for your engine--the reason most newer engines have a provision for pulling engine timing to eliminate the knock.

I think someone mentioned Seafoam cleaner in a previous post. It does a pretty good job of removing deposits. Run some 93 octane, if there is a noticable difference in performance, you have found the problem. If the high octane fixed the problem, give your engine a Seafoam treatment. By reducing the deposits will lower your octane requirement. If you go back to the lower octane after the seafoam, the problem may come back eventually. But you'll know the fix, repeat the treatment.

Try to use "top tier" fuels. Chevron and Shell along with a few brands I can't remember meet the top tier requirement. They have more detergents and other additives that reduce deposit formation.

Info on top tier fuels:


07-27-05, 10:04 PM
I think someone mentioned Seafoam cleaner in a previous post.

This Seafoam is good as gold. I did a basic tune up on a buddies truck with a similar problem . I've dumped Seafoam into the fuel tank, the crankcase, and removed the pcv valve and dumped it into the engine there. When we fired his engine up his truck made a mushroom cloud of white smoke for almost 10 minutes. This is a great suggestion and a really cheap solution.

Here's a link on Seafoam's uses:

http://stevenbigler.tripod.com/scoutco/id14.html (http://stevenbigler.tripod.com/scoutco/id14.html)

07-27-05, 10:04 PM
I got down to 3/4 of a tank so I added 5 gal of 91 octane to my tank today and the problem stopped.

07-27-05, 10:08 PM
I got down to 3/4 of a tank so I added 5 gal of 91 octane to my tank today and the problem stopped.

I agree with Dank.....get yourself some Seafoam and do a driveway carbon cleaning. It will make a huge difference.

07-28-05, 04:39 PM
I did the seaform cleaning this morning...you guys were right. Runs like a dream now.