Hey everyone,

I've looked around here and found ideas regarding these problems seperately, but not together. Anyway- just wanted to get some opinions on what might be causing this. I have a 2001 2dr, 2WD Blazer, 4.3L. with 190k miles on it.

Current problems:
1. The truck is missing, seems like a fuel restriction problem, when in gear and when idling.

2. The truck takes a long time to start (5-10 seconds, consistently) unless it has been unused for 2-3 days.

3. I'm getting bad fuel economy. I calculated yesterday that I drove 33 miles, but my mileage counter showed that I drove 60 miles. Granted that is an estimator and I also turned my truck off / on several times throughout the day.

4. There is a squeaking noise coming from the rear of the truck (may be brakes, but it does it when I take off, turn etc as well as braking. This is the least of my concerns currently.

What I've replaced and why (in approximate order):

2-3 years ago - Cylinder heads were resurfaced
2-3 years ago - Fuel Pump replaced (w/ AC Delco part)
4 months ago - replaced the front brakes (I thought this was causing the squeaking, but only after I replaced them, I found that the noise was actually coming from the rear.... Oh well, new brake pads on the front...
3 months ago (right after the starting / missing started) - Replaced the Water pump, thermostat, hoses, etc. (for overheating / seperate issue), the timing box / chain wasn't touched. Someone said it might be off, but I don't beleive that.
3 months ago - replaced the Air / Oil filter (routine maint.)
3 months ago - replaced spark plugs and wires with Platinum 2 prong plugs (this might be worth noting - one of the plugs, I forgot which one, was fouled out and looked a LOT worse than the rest of the plugs.)
3 months ago - replaced fuel filter
2 months ago - replaced battery
2 months ago - removed sensors on top of motor (EGR, MAF, and MAP I beleive) to see if there was any change in how the truck ran. I thought there was a difference when I unplugged the sensor to the EGR valve, but if there was, it wasn't significant.
this month - cleaned throttle body and the plunger assembly that sits on top right of the T/B assembly (forgot the name of it) with carb cleaner but didn't notice a significant difference).

I know that's a lot of information, and I'm fully aware there might be multiple problems that just happened all around the same time, but I wanted to get y'alls input. I'm comfortable with replacing most of the parts on my truck, but I'm skeptical to go out and buy 6 injectors to replace as they run about $75 / piece which is a lot to spend just on a guess and process of elimination. Any input is helpful!!

Thanks,

John P.

 

Surely SOMEONE has some input or ideas.....?

 

Considering the multitude of posts with very similar symptoms, a little reading may provide help. The #1 thing to do is test the fuel pressure.

You would also find out that the multi-ground plugs are a gimic and actually will end up being problematic in short order. AC Delco double platinum plugs just seem to work better in these engines.

Calculating fuel economy using the numbers on the driver information center is worthless in my opinion. The only way to know your true mileage is to divide the # of miles traveled by the # of gallons pumped. But you have to be consistent as well by always stopping at a certain point (i.e. when the pump clicks off the first time). Keep a log and compare. Shop around. You may find that certain gas stations agree with your truck better than others.

Again, many of these same recommendations have been made in a number of other posts. There is a wealth of information at your finger tips.

 

I would wait for swartlkk to answer this, he seems to be the answer man around these parts.

Now if ya want my half-a$$ed opinion, I would guess that #1 and #2 are related. Check the fuel line pressure. As far as #3 goes, try a GPS to track your driving and see if the MPH & MPG match up to what the truck is telling you. On to #4... Bent backing plate? Does it have disc brakes in the rear? If so it could be the squealers that are on some pads to let you know they are getting low, or just dust. In drums it could also be dust. Brake related noises usually make sound, or change sound when the brakes are applied. If this is a constant sound, that does not change when the brakes are applied, then I would look elsewhere.

EDIT: Your in luck. Swartlkk posted as I was writing!

 

I have the exact same vehicle and was having almost the same problems, and I just got done replacing my lower intake manifold gasket. That solved almost everything and the truck ran great for several days, but I'm still trying to find out what's causing a slight stutter at idle. It doesn't die like it did before, but it is stumbling intermittently and dripping a lot of water from the exhaust at several points. Maybe a vacuum leak, maybe something in the exhaust (cat) was messed up by my intake gasket situation.

And I tell ya, those LIM gaskets were absolutely destroyed around the coolant ports. When I pulled the intake off it looked horrible and the only parts of the gaskets that were even semi-intact were the parts around the intake ports. The rear coolant passages were plugged with solidified coolant, although the front passages looked perfect.

I originally had the upper intake off in order to change the fuel injectors, and I happened to look at where the intake meets the heads and I saw what looked like a glob of oil sludge on the front driver's side corner of the lower intake. I used a screwdriver to try to scrape it off, but when I touched it I noticed that it was actually gasket material that had been blown out. When I pulled off the alternator and heater hoses I noticed that it was blown out on the front passenger side corner as well.

When you resurfaced the heads did you use an OEM gasket for the LIM? I'm glad I paid extra for the Fel Pro "problem solver" gasket set, because after removing the corroded OEM gaskets I have absolutely zero confidence in those things to last as long as I plan on owning my truck.

Anyway, I just wanted to suggest checking to see if there are any coolant leaks around your LIM gasket. If so, this could also have something to do with that cooling issue you were having. I had to replace my radiator during these repairs as well because it was cracked.

In case you're curious, to remove the solidified coolant from the rear intake passages I just chipped away at it with a screwdriver and then put my shop vac hose over the opening to suck it all out. If I covered the front coolant port with my hand it made a pretty strong suction and all the loose pieces came right out.

Hope this helps.