Troubleshooting an intermittent sputtering problem

[Brett5cent]

Hey TV people, ok so I’ve got an issue going on that I can’t seem to figure out.

I was on a trip to Tahoe recently, the van was already struggling because of the altitude. But the second day in, I was really having to gun it to get up some of these steep Mountian highways, running it HARD. All of a sudden I just lost all power and my engine was just sputtering, sort of like heat soak but not, and way worse. Loss of pretty much all power, I was doing like 20 mph uphill. I’d pull over then it would resolve itself so I could drive another 10 min, then it would happen again… and again…

Since then it has continued to be an issue and it’s driving me crazy. I want to know what you guys think this could be. My thoughts range from the ECU taking a turn for the worst, to clogged fuel injectors.

I’m kind of thinking maybe my TPS (that was from a donor) could have been damaged from the constant stomping on the pedal to make it up hills, but would a broken TPS cause this sort of issue? And why would it go back and forth from running great to running terribly?

I’m out of ideas, someone please shoot me thoughts.

[Burntboot]

I don't think stomping on the gas pedal can hurt the TPS, otherwise, there would be a heck of a lot more failures.

You will need to do some detective work to determine the source of your fault.
(assuming there are no outstanding repairs or maintenance pending, that is)

The symptoms are consistent with that of a plugged convertor.
Comparing exhaust flow at the tailpipe should be a decent indicator.

It could also be fuel system related or several other possible suspects, but you might as well eliminate the easy stuff first.

[Brett5cent]

Thanks for the input. That seems a little unlikely but possible. I put a brand new catalytic converter in probably 2-3 years ago. I will get it tested though to make sure…

[Burntboot]

The real question then is why did the previous cat fail?

Generally speaking OEM cat's are considered "lifetime" parts (aka, no replacement needed)
and those that do fail, are either taken by rust or contamination by oil.
Replacing a rusted cat is a no brainer
But if you replaced yours because it was contaminated/plugged, then what ever caused its demise should have been remedied at that time.

The other thing of note is that while a factory convertor should last the lifetime of the car,
an aftermarket replacement cat contains far less precious metals and consequently has a MUCH shorter lifespan.

What is your oil consumption like?

[Cali Cruiser]

The first thing that comes to my mind would be to check the rubber air intake tube for cracks or splits, especially hard-to-find ones in the accordian-looking ribs of the rubber. Be sure to closely inspect on the backside and underside of the tube.

Next guess would be spark plugs that came loose and backed out of the holes. Check each plug (or replace them if they are worn) and torque to manufacture specs. While you are checking spark plugs, check the distributor cap and rotor (or replace them if they are worn).

Most times, checking the simple things that are often overlooked are the best things to do first.

[MarkH]

I'd put a fuel pressure gauge on the fuel lines and see what the fuel pressure is with the fuel pump test connector jumpered. If it's low, the engine could die at higher loads. 1159011591
Also, I don't know how old your fuel filter is, but it might be getting clogged.

[MarkH]

Oh, and also, are you getting a check engine light on the dash? Any of the components feeding into the ecu like oxygen sensor, TPS, etc.... should generate a fault code if they go bad or are out of range. If the computer isn't generating any fault codes, then those components should be fine. An exception might be the oxygen sensor fault code. If you are getting too much fuel or too little due to a fuel problem, the oxygen sensor may read out of range due to a very rich or lean fuel mix reading and generate a code even though the oxygen sensor is working fine.