I'm new to this forum, and I've looked on here for my answer but can't find it. Problem is simple, I have a 1999 B 4X4 4.3L. It had good power and I love this truck. Well it started here. I had a fuel injector go out and had it replaced buy the dealer. After I got it back I noticed a power loss so I thought a tune up was in order. New plugs, wires, and air cleaner. Well I didn't notice much difference so I just let it go. Well it has slowly went down hill with power loss and now it started to heat up. I replaced the thermostat and it is still getting way to hot like 245 F. I tried to clime a big hill over here @ 6% grade and dropped into 2nd gear, What is up with that? I used to go over this hill in 3rd @ 75 mph at half throttle. I thought is was the catalatic convertor so I had it checked out yesterday. Nope they said it only had 4 lbs. back presser. Now I'm getting pissed off. I have looked this thing over a hundred times and still can't figure this one out. Help............Got any ideas?

 

have you had the computer scanned yet? Autozone does it for free.

 

I haven't had it scaned because the engine hasn't thrown a code. I don't think it will help will it?

 

mines having the same problem. I replaced the whole cooling system (radiator, hoses, etc.) and i cut my cat off today and it is fine. but I have almost NO power now and it feels like something is holding the thing back when you hit the gas.

 

I would get a new set of spark plugs and install them. Then let it run a couple of hundred miles, pull them, and see if one or more cylinder's plugs look cleaner or less used than the others. That would indicate a faulty injector that is preventing cylinders from running properly. It may be that the injector which was replaced was fine but the poppet was stuck. I have heard of this from another cruiserhead who swapped a Vortec into an FJ40 (His is a V8). His method for fixing the problem was to disassemble the injector body (after getting at it by disassembling the top of the engine), soak the injector (lower part only) and the hose/poppet in gasoline, and then blow compressed air through the poppet. I haven't done it myself (yet), so proceed with extreme care. He said his poppets opened with a bang and then worked. If I remember correctly, he also put some voltage to the injectors to see if he could get a click out of them. Be careful with that. If you do that I recommend clipping some long test leads to the injector leads and VERY briefly touching the leads (away from the gasoline soaked injector) to a 9volt battery. If you hear no click, the injector is probably gummed up. Try it a few times, to see if you can free it.

I once did some work on my '85 2.8L blazer and buttoned the thing up, and drove it around the block for a test drive. It had no power at all, but seemed to be running smoothly and idled just fine. I then realized that I never reconnected the left side spark plug wires! What you describe sounds like running on fewer than six cylinders!

 

Get a Haynes manual and find the injectors ohmatic values. Test each ones' ohmatic value. It'll probably be under 13 ohms each.

The range for my Impala was something like 11.6-13.0 ohms