2002 s10

[2002ZR5]

ok well i have a 2002 s10 with the 4.3L went to hit the free way today and can't get it over 60mph if i step on it the engine starts making weird noises not really a knocking but more of a pingging or popping sound and it only does it if your going over 40mph if you stay under 40mph it runs like a top if it's in park and you rev it up theres no engine pingging or popping the truck has just over 200,000 on it and need to know what it may be or if i should just sell it and move on thanks

[HenryJ]

Plugged cat or fuel pressure. My guess is the cat.

BLT Offroad tablet

[roadrunner]

Plugged cat or fuel pressure. My guess is the cat.

BLT Offroad tablet

Totally agree! I might add you're lucky you made it that far without plugging the pre or main cat. Mine plugged at 80k.

[2002ZR5]

i think thats what it is i just took if for a drive and got a really bad rotten egg smell and the cat was super hot but the rest of the exaust was only warm to the touch

[HenryJ]

The precat is the first suspect. Time for the sawzall and a look. You can get a SS band clamp to put it back together and make the run to the muffler guru for a weld after "broom handling" it. If the main cat is gone, you may want to do some shopping for a replacement.

BLT Offroad tablet

[2002ZR5]

how will i know if the main cat is done for?

[ApproachMedium]

Rotten egg smell should be the clue that the main is bad/going, also you should get an SES light with P0420 code set in the computer. When mine went it gave me that, it was not totally clogged but was getting there.

[HenryJ]

An internal visual inspection is the only true answer. Temp readings and pressure testing can be done too, but can be misleading in an inexperienced hand.

[alntex]

To Henryj: Pardon my inexperience, but, can you explain "broom handling"? I am considering surgery on precat too. Al

[Lil-j]

This could also be a bad ignition coil as well. Just had this recently, truck ran like crap over 35-40mph, terrible exhaust smell etc. It was the ignition coil causing random misfire's, therefore raw fuel going to the cat, causing the smell.
A bad coil is very easy to diagnose, open the hood and reach for the throttle to rev up the engine. Rev it up and look to the left of where your hand is, when it's revved up you'll see and hear spark, engine run run really rough, you will hear a pop or ping sometimes. Easy fix, especially if the factory coil has been replaced.

Also, you should have misfire codes if this is indeed the problem.

[HenryJ]

"Broom Handling": Using a wooden dowel to punch through, poke, crush, crunch the honey comb interior of the pre-cat so that it can be dumped out creating and open empty shell. Make sure it is very clean. Any debris transferred to the main cat will plug it up and cause it to fail.

[Horsehammerr]

"Broom Handling": Using a wooden dowel to punch through, poke, crush, crunch the honey comb interior of the pre-cat so that it can be dumped out creating and open empty shell. Make sure it is very clean. Any debris transferred to the main cat will plug it up and cause it to fail.

Here in the Ozarks we have no emissions testing, only visual inspection. When the pre. or main cat plug it's "Broomstick" "Rebar" "Prybar" whatever it takes to clean out all that clear-flow exhaust blockage, and away we go.

[alntex]

HenryJ, Thanks for the definition (I kinda suspected sumthing like that). I checked my vacuum at idle 18" and observed a momentary drop when opening the throttle, but it climbed on up to 21" at a steady 2500rpm. I think that is an indication that my exhaust is fairly clear, so I will look elsewhere for low MPGs. alntex