Suburban Power Drop Off

chevrolet
suburban

#1

I have random power drop off (best description is a loss then a surge or something like a skip) when driving over 60 mph. If I let off the gas or floor it the problem goes away temporarily. No mechanic has been able to figure it out. Chevy dealer just says “we don’t have any codes”.


#2

What Model-Year Is This Suburban ?
Faulty TPS ? I Have Seen At Least One Cause These Symptoms And Not Set Any Code.

CSA


#3

Would you be willing to pay a drivability technican a minimum of 3 hrs to inspect,measure,test components related to the drivability of your truck, with an agreement that he still gets paid if nothing is found? Perhaps you will find a tech that agrees no pay if he does not fix the truck. Is it easy to duplicate the sympton? No chance at all this is a torque converter lockup that you are feeling? Perhaps an event recorder will need to be hooked up but this is most likely out of the “no tools needed” group of problems to fixed.

How I would go after this would be to ride with you and see if we could duplicate. If we could duplicate great,if not it would be up to you if we proceede. After the duplication test drive I would check for TSB’s,then get my scanner out and get all the data I can. If no direction is given via the TSB’s or the scanner I give you the option of you paying me to use my experience in working with the data and testing parts that are initally comming up with a “good” rating. If you don’t want to pay for my experience directed path to finding a cause for your sympton,we stop there.


#4

He’s merely asking for advise oldschool. Do you hear any type or rattling, popping or clanking from the exhaust? Materials from inside the catalytic converter can deteriorate and make there way to the exhaust exit and clog momentarily.


#5

The first question is how old your spark plugs & wires are.

The second question is how old the fuel filter is. The fuel pressure should be checked under load.

The third question is whether anyone has put a vacuum gauge on it to look for evidence of exhaust restrictions.


#6

My description is simply how I would expect things to go if he did bring it to a shop again. A good shop will keep the customer informed about what they are doing and where they are going just so there will be no suprises when it comes time to settle up. Based on the very few details we have I am concluding that this problem is not going to be fixed under the shade tree and will require an experienced drivability technican to keep the repair time down and not spend money on parts not needed. I always like to know the year and fuel injection type as there are problems common to certain years and injection types.

I am not saying it is required that the vehicle go to the Dealer.


#7

This is 1 1997 Suburban. No one has mentioned a faulty TPS as a possibility.


#8

I replaced the spark plugs a couple of weeks ago, but the problem is still there. The spark plug wires have never been replaced.

Fuel filter was replaced in 2010 and the fuel pump in 2009.

No vacuum gauge was ever used to my knowledge.


#9

No rattling, popping or clanking noises.


#10

As a test, you can try spraying down the plug wires with WD-40, and taking it for a run. If it performs better, then they’re faulty.

WD-40 is only a quick fix, and will help you for a little bit (as in hours, not weeks), but should be enough to eliminate (or identify) them as a cause.

This is just about the only thing I’d use WD-40 for. I can’t stand that stuff.


#11

I replaced the TPS but this did not work. Onward to other ideas until I resolve it.