Engine bogging down knock sound.

[mixwell]

On the way to work today I noticed as I started to give my truck gas to speed up on the main street my truck started bogging down and lost a lot of power almost as if it were being choked. I just noticed yesterday that my temp gauge will go up close to hot and then drop drastically and then build back up again.

I researched some symptons and someone had mentioned in another post a faulty cat. I was speaking with a co-worker and he blurted out that it was my cat also because he had an identical problem. I'm assuming the exhaust heat isn't escaping and could be the drastic temp fluctuations ? I do know that I have an exhaust leak near the cat..

Any extra ideas would help, I have heard other symptons being fuel filter, misfire, plugs, plug wires, vaccuum lines but it doesn't really sound like it's a misfire, it does run smooth at idle but when you give it decent gas it's creating the issue.

Thanks in advance

 

[Rearanger]

It's hard to suggest solutions when you've done no personal diagnosis, except a list of possibles. A ten year old CAT should not be blocked unless you had bad oil burning or very rich run. A vacuum test would show blocked exhaust. Why don't you take the CAT off and see if your problem goes away.

 

[mixwell]

It's hard to suggest solutions when you've done no personal diagnosis, except a list of possibles. A ten year old CAT should not be blocked unless you had bad oil burning or very rich run. A vacuum test would show blocked exhaust. Why don't you take the CAT off and see if your problem goes away.

Well I'm in California so it's by law I have to have a cat on my truck, yea I really didn't have time to check anything as of yet, I turned around and drove another vehicle to work. I do notice black carbon buildup at the muffler tip for what that's worth and I do lose about 1 quart of oil every 1-2 weeks with no leaks showing up so oil burning could very well be a possibility.

I will read some more for the time being until I can get off work to look at the truck. Thanks !

 

[Rearanger]

Well I'm in California so it's by law I have to have a cat on my truck,

But you'd only be taking it off for diagnosis, not full time.

I do notice black carbon buildup at the muffler tip for what that's worth and I do lose about 1 quart of oil every 1-2 weeks with no leaks showing up so oil burning could very well be a possibility.

If it's the CAT that's only a symptom, you need to fix the oil burning or you'll be replacing a new CAT before long as well. How many miles on this truck?

 

[mixwell]

Approx 111k on the truck currently

 

[basketranger]

and do not forget a blown head gasket allowing coolant out the exhaust will kill a cat, also.

 

[Rearanger]

I do lose about 1 quart of oil every 1-2 weeks with no leaks showing up so oil burning could very well be a possibility.

Approx 111k on the truck currently

Awfully low mileage for that much oil burning. Done a compression check? Possible valve stem seals. If antifreeze leaking through HG to exhaust then you'd have thick, white, sweet smelling smoke out exhaust, not to mention coolant loss. I'd do a vacuum check to confirm exhaust blockage and if, as you describe it, then it will be severe blockage and easy to tell with vac gauge. You can then remove CAT for inspection and maybe put a bypass pipe on in place of CAT to allow diagnosis of oil burning. There's no short cut here.

 

[mixwell]

Thanks for the ideas, man upon checking things out... my radiator was almost dry and the oil change I just did LAST SUNDAY was about 1 1/2 quarts low.. I don't know with a possible clogged cat if this would cause excessive heat and burn up my oil and coolant but man both are low.. i filled my radiator back up and haven't had a chance to pickup oil but ill be driving another vehicle until I get paid this next week and get some stuff for it..

wow it kinda feels like my truck is taking a dump on me but I'm getting a gut feeling with the cat clogged (assuming because weak pressure coming out the tailpipe) that it's causing my engine to run hot and burning up my coolant and oil. I will hopefully get to messing with it next weekend when i can get some funds but for now I'm going to try and drive it as little as possible.

 

[Rearanger]

I'm getting a gut feeling with the cat clogged that it's causing my engine to run hot and burning up my coolant and oil.

You're looking at this backwards. Oil and coolant caused clogged CAT. I'd look for blown head gasket.

 

[stmitch]

You're looking at this backwards. Oil and coolant caused clogged CAT. I'd look for blown head gasket.

Agreed. A clogged cat is usually the result of another issue, like unburnt fuel escaping into the exhaust. I've heard several people with 01-up 3.0's that have had similar problems caused by bad valve seats. Could be another possibility to consider.

 

[fourwheelford]

Man gotta keep up on those fluids, I check mine every week at least. Do a compression test to see which cylinder is leaking, its probably been doing it for awhile other wise you would have noticed a giant plume of steam behind your rig.

 

[mixwell]

Took my truck to a shop and they confirmed cats are not clogged AND i found where my coolant is leaking from a pinhole on the termostat temp unit. Possibly this weekend i can run a compression test but forget do you run a comp test with all plugs taken out ? Haven't done it in a while.. I do have a remote starter gun that connects to the starter so good on that..

 

[Steiger Man]

My 86 had this same issue. It would run fine, rev up and everything. When I put it in gear and run on the road it would fall on it's face and rattle. Then it would start to get hot. when I pulled over it would cool off really quick. I found that the distributor clamp was loose and the timing was way off. I don't know if your newer truck has a distributor or not, but that's what happened to me.