4.3 blazer stalling out on me

Sup guys I just bought a 98 S10 Blazer with the 4.3 v6. Which stalls out when I give it gas when its in first. A slow accelration it wont do it. But if I floor it it cuts out and chokes on me. Or if I try to foot brake it and give it gas it chokes and dies. I have a code its a PO420 which is catalyst efficiency low-bank 1. So what i want to know is it the cat or somehting else cause at AZ the code causes were the cat, engine misfire or running condition, Large vacuum leak, and the big one engine oil leakage into exhuast valve guide seals. piston rings. The truck also has a bad valve tic. So what you guys think? Go down the list fixing things. HELP!!! Thanks

I would check the cats.

It has one cat with the standard 3 bolt flange. Which 2 nuts are striped so ill have to cut them. And I want to make sure its most def the cat before I go cutting away. Theres not any abnormal heat or anything but I also think its the cat just wanted some feedback from you guys.

Hit the cat with the wood handle of a hammer and if it raddles then theres your problem. It happened to a buddy of mines truck. He put a new cat in it and good as new.

Start out with a fuel pressure check. Make sure its within specs. After that attack the cat.

Never done a fuel pressure check how would I go about doing this?

P0420 is a bad cat 99.99999% of the time. It doesn't mean it's stopped up or the stuff is loose inside....it does mean it's lost its ability to clean the exhaust. A fuel pressure check using an appropriate gauge installed on the pressure tap inline with the fuel supply pipe behind the throttle body is needed. You need 53-64 under the conditions causing the problem.

So what would you suggest is the problem? It happened agian tonight I left the gas station and the exit has a crude dip so while I was accelerating into the dip the truck cut off right when I got on to the main road. I had to restart the truck. But can I get the fuel pressure check guage from AZ?

There could be a loose ground, a wire broken inside its insulation that opens a circuit under certain conditions, a weak fuel pump....etc.

When engine movement is involved in the duplication of a complaint, many times there is a wiring issue. Manipulate the engine wiring harness while it idles in park and see if you can reproduce the problem. Pay particular attention to the areas in the harness near the transmission dipstick tube, the ignition coil, and the crankshaft position sensor.

Restarting after a stall also could indicate a wiring issue. Most times the fuel pump and the ignition system, especially the coil, either works or does not. Sometimes pumps can briefly "heal" but usually must sit for a while too cool off after a stall or take a bumpy ride on a wrecker to get the brushes jostled loose.

How would I know what wire it is? And what do you mean like try to reinact the problem by shaking the truck while its parked. And would a haynes manual tell me how many grounds there is like chassis arounds I could check. It also chokes when I foot brake it and goes to die wont go past 2000rpm's. And the truck doesnt restart by it self I have to do it manually

Ben--the lean condition is happening cause the PCM is not getting the reading after the cat it wants. There is obviously too much unspent exhuast gasses passing through the cat--so the PCM is cutting back fuel. I would do the easy/cheap stuff first--have the O2 sensor checked to see if it is good still (they go back QUICK if the cat has gone south), check fuel pressure on the Schrader valve by the TB (looks like a valve stem on a tire), and tap on the cat with a bunt hammer to see if it rattles. After that, do a new cat. It should fix the problem...

Thats by plan Tyler. I just replaced the orginal fuel filter with 138000miles on it. And just ordered a universal magnaflow cat from summit for 60.00. Then im doing new plugs wires this friday. Thanks for all you guys help.

P0420 is caused by the elements in the converter degrading. Most times a plugged converter is an EFFECT of a misfire. You need to make sure the rest of the engine control system is in good order or the new converter will die as well.

Just did new plugs and wires. Dropped the fuel tank today found a freakin hole in it (SIGH). And a cut ground cable that is grounded to a peice of metal thats between the fill neck.

That ground is there to keep you from exploding when you fill the tank....it won't make it run bad if it's broken.

Ok but ima fix it anyway that would suck. But I have to replace the fuel pump now since one of the connectors went SNAP! damn thing was the stock pump. Guy I bought it from said it was new. But ima check the O2's 2marrow

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Originally Posted by GasGuzzler

That ground is there to keep you from exploding when you fill the tank....it won't make it run bad if it's broken.

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I should probably fix mine then... lol

Maybe...LOL