Today my 2000 Ranger lost power and started bucking severely going up a hill. I suspect a plugged Cat. Doing an infrared thermometer reading, the cat under the truck read around 500 degrees before the cat and 200 going out.
My question is should I be holding the infrared gun on the pipe as it exists the second can by the oxygen sensor or between the two cans. Thanks

 

Yeah, way to cold!

 

I'm going to recheck tomorrow. I just am not sure where to check the heat. Between the cat and resonator or on the pipe after the resonator. Not sure if that's a shield between the two cans.

 

something I found when my cat went was that I could hit it with the heel of my hand and hear "stuff" in there. Basically the media had broken apart on a front one and blocked the back one.

 

Buy or rent a vacuum gauge and Google on how to use it to check for a plugged cat.

 

I should have checked it with vacuum, but to late now. I removed the cats under the truck.
It doesn't rattle or do the screens seem dirty. Is there a way to check if it's plugged.
Today I checked the heat on inlet and was about 460 degrees. The outlet was around 330 degrees.

 

Lets think about this some more. Lots of unknowns. What makes you suspect a clogged cat converter? Has / Is the CEL been lit for a while with codes indicating a over fueling problem that would cause the cats to run hot having to process unburned fuel?

If so, scan the ECM for trouble code clues & post up All code clue Numbers.

If no code clues but it runs ok & not overheating at high speed on a level road, or if the exhaust pressure at the tail pipe doesn't seem restricted when you put a hand close when a helper gooses the engine rpm, or the cat converter/s aren't glowing cherry red when it goes wimpy on uphill power, or if you don't get a serious drop in vacuum when performing the clogged exhaust test scenario 14 with a vacuum gauge attached as indicated here Vacuum Gauge is an Invaluable Tool when Diagnosing Engine Problems, then consider with the engine going wimpy & rough on up hill power, suspect a under load spark / too wide a spark gap having the spark blow out under load, or a fuel delivery problem like / low fuel pressure / low delivery rate, like a clogged fuel filter, or wimpy pump, or a kinked fuel line, or other fuel trim problem from say lazy O2 sensors, or if its pinging when it goes wimpy & bucking on the uphill pull, then also look to a clogged air filter, or air intake tube before the filter, as critters like to build nests behind the passenger side inner fender liner. SO, let the trouble code clues, or your vacuum gauge tests also help focus your trouble shoot.

A bunch more thoughts for consideration, let us know what you find.

 

Agree with above.....your suspicion about clogged cats was a good one, and I give kudo's to your git er done approach, which it sounds like the cats are not the issue assuming as you stated they look clean internally and there are no internal rattles/particulates, etc...…. but that is really good news too that the issues is likely a much cheaper fix!!!!!!

 

Let me give you guys a little more history. When I bought this truck a few weeks ago I didn't pay very much for it. The previous owner said he thought it might have a blown head gasket. About ten seconds after start up, excessive white smoke comes out of tailpipe for 1-2 minutes. It then clears up for the day. I had a sniff test done and mechanic said it wasn't getting exhaust gas in the cooling system. Had it scanned for codes. 02 sensor bank 2. He cleared the code and said to drive it. All 02 sensors seem to look brand new. I replaced the plugs and wires and plugs look good. Sunday morning I fired it up and it was smoking pretty bad. I started up a hill and it started bucking really bad with loss of power. I pulled the cat off and there is absolutely no white smoke at start up. I'm not sure what to do now. Thanks again

 

Ok lets think about the above info some more. If you suspect a coolant leak, it could be a manifold leak & not show up as a cylinder problem, but if its a exhaust manifold leak, lasts long enough on a cold start, it might show up as exhaust gas bubbles at the radiator cap when its cold. so with the engine at cold idle remove the radiator cap & have a look-see/sniff for exhaust bubbles in the coolant.
If its leaking coolant into the exhaust, the morning puff of vapor/steam/smoke, should smell sorta sweet, like anti-freeze, so have someone start this puppy up while you do the morning exhaust white cloud sniff test.
If its leaking coolant into the cylinders from a intake manifold, or head gasket leak, you should have seen signs of a squeaky clean steam cleaned spark plug from that cylinder. So if its leaking coolant into the engine, you should see the coolant recovery tank level drop over time.
Coolant into the exhaust will kill the O2 sensor in that bank quick, it killed my 99 4.0L O2 pre cat O2 sensor in 3 miles, after a Dealer/Factory under warranty head replacement. Apparently when they opened things up, a little anti-freeze got into the exhaust, so when driving home on the freeway to check things out I got a CEL 3 miles down the road. They confirmed the lazy sensor & replaced it under warranty--lucky for me. From the faulty sensor we knew which cylinder bank the leak was from. Over time they replaced the head gasket again on that side + new heads on Both sides & Revised head gaskets on both sides again in 02, which finally fixed my coolant sipping problems. So if you have a slow, or intermittent coolant leak, be prepared to be patient trouble shooting it, as it might take some time to accurately trouble shoot it.
You could try retorquing the intake & exhaust manifolds & the heads if any of those suspects end up on your suspect list.
We also did dye tests in the coolant, then looking for leak signs with a black light, no joy there, but you might have luck with it if yours smokes on a cold start. Mine only showed a very slow/6 weeks recovery tank fluid level drop, so it was sipping so little of the dye spiked fluid, it wouldn't show up with the black light test.
More thoughts for consideration, keep us posted on your findings, will be interesting to hear what you find the root cause to be.

 

No sweet antifreeze smell. I have a red marked line drawn on the recovery bottle with no apparent antifreeze drop. Spark plugs all looked the same color.
There are times when after starting the truck, it will have a puddle of water under the tail pipe. What I don't quite understand is why I don't have white smoke coming out of engine with converter removed, if I have a head gasket problem? One good thing is that my brother in-law owns a junkyard. I can throw a lot of parts on it at no cost.

 

No sweet smell in the exhaust on the first cold morning start white puff would be a good sign. Seeing a puddle of water under the exhaust pipe, or a puff of steam/white cloud after a cold morning start is normal. It not doing that with the cat converter removed might be expected to be normal as the cat converter isn't there to Quickly heat any small residual moisture in the exhaust plumbing & quickly turn it to steam, so that might be an explanation of why your not seeing the white puff with the cat converter removed from that side.
If the recovery tank level isn't dropping below your mark over time, is a sign that its not leaking, or that the leak is so small & or quickly self sealing with some heat, that its not presently likely a problem but may get worse with time. It might also be a clue that if there is a tiny leak it might be a head or exhaust gasket as they are the first to Quickly get hot & expand after a cold morning start, so that might sorta put a intake manifold leak lower down on the suspect list.
You could perform a smoke test on a cold engine to see if you can spot a suspect area. If you don't have, or can't come by a smoke machine, you could try rigging one using some rubber tubing, a Swishers Sweet Cigar & blowing its sweet smelling smoke into a vacuum line or port fitting close to the intake manifold, then use sight & smell to spot any leaks in the intake or exhaust manifold gaskets or plumbing. So since you suspect it might be a cold leak problem, do the smoke test on a cold engine, say after it sits overnight & have it parked where there is no wind, or strong drafts to blow any small puffs of smoke or smell away.
More thoughts for consideration, let us know what you find.

 

Thanks, all good ideas. Still doesn't explain the severe loss of power and bucking I got on Sunday. I went to my brother in-laws junkyard and gutted a cat. Going to put it on and see what happens. I will not make it permanent.

 

You may have more than one problem.

 

I started the truck this morning with the gutted cats and exhaust hooked up. I got white smoke at start up for a minute or so. I took the truck for a ride and felt slight miss lugging it going up hills. I started it back up an hour later and drove it about 15 miles and it seemed fine. I hooked up my vacuum gauge and it read a steady 21 psig. I had a helper rev to 2000 rpm and vacuum stayed steady.
Not sure what route to go now. Maybe have AutoZone check for any new codes.