99 GMC Jimmy Misfire problem

I've got a 99 Jimmy 4.3l v6, I've got a misfire code on cylinder 4, I've replaced all plugs, wires, dist. cap, I've still got that damn misfire code and 10 mpg on the highway, can someone please give me some suggestions as to
what to do. If this helps this all started when my old lady ran the truck out of gas about two weeks ago.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Adam,
I'm a GMC tech., and I also own a '99 Jimmy. The 4.3L engine has had many issues with the injector poppet nozzles sticking. You can try adding a bottle of Chevron's fuel injection system cleaner (buy at K-mart, Wal-mart, or local auto supply), added to your gas tank. GM dealers also sell this stuff, but they re-label it and give it a GM part number, and then charge more cash. If this dosn't help, take the truck in to have the injectors cleaned. They will run the cleaner directly into the injector fuel rail. As a last resort, the injector need's to be replaced.
GMdude
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Adam,
One more thing,.... Make sure you purchase the "Chevron" injection system cleaner. For some reason, this stuff works. It has an additive called "Techron". This Techron additive is also available in "top-tier" gasoline. Major fuel suppliers, are starting to add the Chevron additive directly into the gasoline you get at the pump, but progress is slow.
When you run your fuel system dry, and oxygen is introduced, corrosion sets-in. Injectors have microscopic holes/orifices. You just need a tiny speck of rust to plug an injector.
Gasoline is a corrosive. As long as a steel fuel component is submerged/filled with gasoline, corrosion will be at a minimum to none. Once the steel components are exposed to atmosphere, they start to rust. This can take less than an hour.
Don't blame wifey for this problem, ... She didn't know.
GMdude
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks for the suggestions, I will buy some injector cleaner and put it in, I will be sure to buy the Chevron brand. Another thing, if I do have to get the injectors cleaned I can buy the cleaner in the can and hook it to the fuel rail myself probally, I know I've done it on a few fords. The GM dealer may be different, they may not sell the cleaner in cans.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Adam,
You can attempt to clean them yourself, but there is always a chance that the injector cleaner will make it back to the fuel tank. Injector cleaner is pretty nasty stuff. It has to be, in order to get the injectors clean. I have seen some issues with a vehicle needing a new fuel pump, after injector cleaning (Usually on a higher mileage vehicle). Not too common, but it dose happen.
I have devised a plug that I insert in the return line, that doesn't allow the cleaner to get back to the tank. There is no way to pinch-off a return line on this vehicle.
If you try cleaning them yourself, I suggest you have a full tank of gasoline. This way,... any cleaner that gets back to the tank, gets diluted well.
As for the TCCM,... your out of luck. I don't know of any "easy way" to shift the transfer case, without it. I suppose if I looked through the schematics, I could find some way to make the transfer case shift, but it's not worth the effort. This automatic transfer case is electronically controlled. The TCCM is on a communication buss with the PCM (powertrain control module). I have a spare module at home, but I'm not willing to part with it. I know that one day, I might need it.
GMdude
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I put that Techron cleaner in our car tonite and a full tank of gas, still hasnt made any difference but I will give it a tank of gas at least to run through.
Do you think you could be able to find another TCCM for me? Around here they are scarce actually I've called all salvage yards within 200 miles and no one has them, because we have the 4 switch control. If you could find me one I would greatly appreciate it.
Thanks

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
well, I tried ur suggestion of chevron fuel injector cleaner and it failed. So what are my next options?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Adam, I seem to remember you stating that you added one bottle of techron to a full tank of gas. IF memory serves the large bottle will treat 12 gallons. It doesn't work overnight. You may need to run several tanks of treated fuel through your injectors to clean them up. I run a tank of treated fuel through my truck once a month or 6 weeks just because. Regards, JR
--


---------------------------------------------------------------------
"Eliminate annoying spam!
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I filled up the tank, and I used 2 bottles, I know it was like 13 bucks for both of them
And since that tank, I've ran almost 2 more tanks of gas and techron through the truck.
I drive it everyday at least 100 miles, I'm lucky to get 100 miles on a tank of gas right now. And I keep getting that damn misfire 4 code

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Since your a GM tech answer me this, can I engage the 4x4 without the TCCM being in place? Is it vaccum controled at all like the 80 - 90 models? I have looked myself ragged and cant find the 4 switch TCCM, everyone has the three switch. Mine has auto 4x4.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Have you done a compression test?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Nope, but its gonna be getting done soon. That was next before the injector cleaning

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.