Heath Lawhon

Bear with me, this is a long one. I need help figuring out what is wrong with my S10 please. The truck is a 2003 S10 LS extended cab with the 4.3 V6, it has 130k miles on it and has had regular maintenance. It is a two owner truck, my sister in law and then me. I have had it about two years, shortly after I got it the fuel pump began to whine so I expected it to need a fuel pump. Every now and then it would be hard to start after being driven and then sitting, such as going to lunch and then starting back to work, or it had a rough idle that would smooth out after running for a few seconds. Back in December of 2019 it died on the highway while my wife was driving it. She was accelerating onto the interstate and it died "like it was switched off". We were leaving town for Christmas so I had it towed to a shop I know and trust. I figured the pump had finally gone out but the guys checked for pressure and it was good, they discovered that the metal contact was gone from the rotor button. They just charged me $20 for the new part. A few weeks later it was hard to start after I had been in the grocery store for about 45 minutes. It ran rough but didn't ever smooth out, about a block from home the check engine light came on and I eased on into the driveway with it. My OBD scanner gave the code for a mis-fire on #3 cylinder. Not being sure how old the rotor had been I decided to do a tune up. I replaced; plugs, wires, distributor cap, pcv valve and fuel filter. The mis-fire and rough idle persisted and continued to log the code for the #3 cylinder. I did some online research and discovered the problem with the spider fuel injector system going bad. I drove it to the shop, about three miles, and they looked at it and agreed it was an injector stuck open as there was very heavy fuel smell. I ordered a new unit from partsgeek.com and installed the new spider injector unit. It started and ran fine unless it was already warmed up, then was hard to start like before. I decided the fuel pump must be the problem as it was starting to lose power on the top end when trying to pull out to pass on the highway. I replaced the fuel pump and it started and ran fine until I drove it. It bogs down now at all speeds. It will idle and rev up fine but under load it has no power, no throttle response and it used to be able to light up the tires, it makes a muffled roar under the drivers side hood when you try to accelerate as if straining for air to go in. I drove it around the block with the air filter out and there was no change. In addition to the new plugs, wires, distributor cap, rotor, pcv valve, fuel filter, and fuel pump it has a new air filter, I have cleaned the mass airflow sensor and even disconnected same to see if it would go to a "neutral" position to determine if it was bad. All that did was give me a check engine light and code for the sensor. I have checked for vacuum leaks around the intake where I had it out, and at idle it will hold 18 - 20 inches of vacuum. It has always seemed to generate A LOT of heat under the hood but has never run hot, the gauge never goes above 210. The oil pressure gauge is also "twitchy", but shows good pressure. I know these are notable for the distributor drive gear wearing and having too much play, could the ignition coil be "slowing failing" (I have never heard of a slow demise, they always just go out), or could I have a stopped up catalytic converter from the miles driven with the #3 cylinder flooding? Getting tired of thinking I have it solved and then it getting worse, and throwing time and parts at it. It has not logged ANY codes with the current loss of power. Any help and insight is greatly appreciated!!

Little Bear

Clogged cat could be it, pull an O2 sensor and see if it runs better with the exhaust having an out before the cat.

Heath Lawhon

Finally got the time today to pull the O2 sensor. Only a very very small difference, it still bogs down and is loud as hell. It may be my imagination but it seemed to get a little worse after it warmed up. it also did NOT give me a check engine light with the O2 sensor missing, I expected one immediately.

Heath Lawhon

I noticed yesterday when I was driving it on some test runs, not only does it still bog down when I try to push it hard, I also get valve train rattle. I pulled the distributor and it has a fair amount of play side to side and up and down on the internal shaft. It also makes a bad grinding/squealing noise when turned by hand. Some of the drive gear teeth look worn too. May or may not be my problem? But it can't be good!

hogbiker

worn Dist. def could cause your symptoms...especially having the broken rotor tab history...can only IMAGINE the cost and the PITA THAT repair would be..even dyi spider injectors is a PITA job I wouldnt even attempt!!!.....please keep us advised and good luck

Heath Lawhon

I did the spider injector unit myself the other month, it was NOT fun or easy. The new distributor came today, hope I can get it in this afternoon. Getting the old one out was pretty easy, the longest time spent was getting to top dead center before I pulled it. I will update with more, THANKS!

Heath Lawhon

I got the new distributor installed and it still bogs down. I took off the entire plastic air intake system and ran it in the garage to look and listen to what it does. When it is revved up you can hear the throttle body roaring like it is trying to suck in more air. At 3000 rpms it bogs down and I get valve train rattle like bad gas or what used to be called octane ping. Is it possible I ordered or was sent the wrong spider injector unit? This truck has the X vin, but I was never asked when ordering the spider injector.

Little Bear

All the 4.3 spiders are the same. Sounds like at 3K you are running lean, I'd put a pressure gauge on the fuel line and make sure the pump is keeping up.

hogbiker

Sorry to hear a new Dist didnt solve the issue..I was banking on it...darn!!!,,btw, I too, get that "valve train rattle" noise when I "HOSS" on my engine (157k on 'er)...beginin' to think Chevy's 4.3 Vortec wasnt a well made engine, as well as it's overall on-board computer system

Heath Lawhon

I hooked up the fuel pressure gauge and drove it around the block. Pressure was always between 53 and 60. It is getting worse, I barely made it back up the hill to the house. After each drive I put my scanner on it to see if any codes are stored. This time it gave me P0101 which is MAF sensor error, this is the first time it has given this code. I did a test of the MAF, with the switch on it was receiving 12.8 volts, at idle it was sending out about 4.2 volts to the computer, when revved up it dropped to 3.8 and went down as low as 3. My next guess is bad MAF sensor? Before all this, I have never gotten valve train rattle. this little truck always seemed ready to pull the paint off when you hit the gas. From a stop it would boil the tires on dry pavement.