what else for my engine?

I have a 4.3 X, and have tried everything. I have gotten wrong info on many things, and just want my engine to stop missing. We have done plugs, wires, cap, rotor, PCV, ignition coil, fuel filter, camshaft position sensor, O2 sensors, checked EGR, cleaned throttle body and plate, run injector cleaners, tried air filters, and checked all electrical connections. When we took off the throttle body, there was gas in the intake and on the throttle plate, along with alot of carbon. Everything started after a tune up, and we have checked and rechecked all the work. Nothing is crossed, and we have tried different brands of everything. At one point, the service light was on for a cam position sensor circut malfunction, and a hard misfire. But the truck ran wonderful and never missed a beat, and was running rich. We are at a loss, the spider lines look good, no cracks. If it is warm and dry outside, it runs great. But bring on a cold rain, and bam. Anyone have any ideas. Without a service code, we are at a loss. Any help would be appreciated. :confused:

You have a fuel leak, there should be no fuel in the intake, only a nice layer of black carbon. Check to see if there is gas in your oil. If there is, you shouldn't drive it until the injection is fixed or you could damage the engine.

MAF sensor.

Remove, clean the sensor filiment wires with TB cleaner and a toothbrush gentlely and rinse with TB cleaner after to remove the black gunk on the sensor filaments.

Thank you both. There is no gas in the oil, so I guess that is good. We will check the lines, and injectors. MAF sensor is clean, was one of first I checked. Thank you though. If none of this works, know anyone who would like a 4.3 with a 10 guage slug imbedded in it? :evillol:

And, really quick, does anyone out there know where I can get different injectors that would fit my setup. If I have to replace them, I don't want to put in ones with the poppet valve. This is not a project I want to under go every 2 years.

You're welcome.

Due to the fuel puddles in the intake, the injection is the most likely culprit. GM does have an updated MFI to replace the CSFI. The MFI does away with the poppit valves. I have a service bulletin from GM that I can email to you, if you would like.

Another to check would be the firing order. You said," nothing is crossed".....you do know that 1 and 3 are suppose to be crossed...right? It is a common mistake for people to connect the wires to the cap:

6 5
4 3
2 1

They should be:

6 5
4 1
2 3


http://www.image-hosting.ws/direct/1361.jpg

Blazee, please e-mail me the service bulletin. If a dealer has the parts, that would be helpful. Also, I want to try and get the New York State involved, as well as any other states possible. This just is not fair. People everywhere are failing inspections because of the federal clean air act. Also I do have the wires correct. I was a little confused at first when I looked at the firing order for the engine, and then the cap. kinda strange-but what do you want. Thank You for your help. Danielle @dtl379

Do you know how I can get a hold of the truck's Canadian history?

I need your email address to send you the service bulletin.

Luckily in Florida we don't have inspections. Seems like most of the people that come to these forums needing help are ones that just failed their inspection.

I don't know how to get the Canadian history.

Blazee, please e-mail me the service bulletin. If a dealer has the parts, that would be helpful. Also, I want to try and get the New York State involved, as well as any other states possible. This just is not fair. People everywhere are failing inspections because of the federal clean air act. Also I do have the wires correct. I was a little confused at first when I looked at the firing order for the engine, and then the cap. kinda strange-but what do you want. Thank You for your help. Danielle @dtl379

Do you know how I can get a hold of the truck's Canadian history?

Make sure 1 & 3 are setup properly.

It is often overlooked.

thank you everyone. I just wanted to know if anyone knows how to get the canadian history. I found out that the truck was built in Jersey, shipped to canada, then at some point sold back into the US. We were never informed of this, and GM of Canada said that all vehicles sold into their market has the odometer in Kilometers. My truck now reads in miles, so something was either swiched out or turned. I want to confirm the mileage, but GM doesn't have any record of the truck being brought back to the US. They said they didn't turn the odometer-so who did? GM also with not give me any of the trucks history. I dont want names of past owners, just the trucks vehicle history.

Get a carfax done on the VIN number.

Does that include Canada's vehicle history? I dont want to spend 25-50 bucks on just the US history.

Does that include Canada's vehicle history? I dont want to spend 25-50 bucks on just the US history.

Yes, it should. Carfax shows both countries records.

We took off the intake plenum and found that we have oil in the intake, along with the carbon layer. We also had a small amount of gas. All the spyder lines look fine, the metering body and gaskets look fine, although they have a tim layer of oil on them. The poppets are spotless on the ends, but have some build up around the bottom of the connection that sits in the engine. :banghead:
We are being told that the oil is there due to "Back Blow" and to try an engine flush to clean out the ports. I wanted to check into this first, and ask if anyone can suggest a good engine flush. I dont want to blow out any seals and gaskets, or ruin any sensors. I have heard mix reviews over doing engine flushes. I also wanted to know if back blow can cause the misfire condition we have been having. Any suggestions?
"I'm finding the idea of a ten guage slug quite tempting right now!"

The carbon and oil is from the PCV sustem. Completely normal.

Just make sure you don't overfill your oil.

Could this cause or agravate a misfire condition? Could it cause sensors in the throttle body to malfunction? Just wondering, and still tring to track down the misfire. THank you.

Is it a massive misfre?

Or is it just a small studder.

I think it is a pretty hard misfire. It can vary in strength from time to time while driving, but you can always hear it while idleing. The mechanic has pulled up a random misfire on the diagnostic machine, but no clue as to where it is. It rarely happens while accelerating, but just about always when holding the throttle steady. It can stop when you let off the throttle though. Sometimes it is so hard that I fear the truck will stall on the highway, but it never does. I NEVER have heard any internal engine componants getting banged around, so I guess that is kinda good. Always run an injector cleaner, and check air breather.

I think the TPS needs to be changed also. The truck idles high for about 3-5 seconds when you turn it on. It can also keep the same RPM speed while driving, even though you arn't using the throttle. It sometimes idles irratically and changes speeds very quickly (a change of about 100-150 RPMs) when you stop. It rarely stays at one idle speed for more than 1-2 seconds when stopped. The RPMs most of the time drop to 400 for a second just after you stop, then start the up and down idle. The idle can smooth out, or it can keep going- its not predictable.

We just changed the idle are valve, and cleaned out the MAP and EGR, and checked the MAF. The PCV just got changed, and we changed the vacuum hoses. We had a P0107 code that now is out. I dont know if there is a vacuum leak, but I think so, so we are going to change the intake plenum and throttle body gaskets. But the truck did this long before the vacuum leak.

I dont know if any of this will help. I may have to take it in and have a shop do the high teck diagnostic machine. I just dont want to spend that much on a tech, when it can go for parts. Thank You.

I think it is a pretty hard misfire. It can vary in strength from time to time while driving, but you can always hear it while idleing. The mechanic has pulled up a random misfire on the diagnostic machine, but no clue as to where it is. It rarely happens while accelerating, but just about always when holding the throttle steady. It can stop when you let off the throttle though. Sometimes it is so hard that I fear the truck will stall on the highway, but it never does. I NEVER have heard any internal engine componants getting banged around, so I guess that is kinda good. Always run an injector cleaner, and check air breather.

What plugs did you use?

What was the gap?

What cap and rotor?

I think the TPS needs to be changed also. The truck idles high for about 3-5 seconds when you turn it on. It can also keep the same RPM speed while driving, even though you arn't using the throttle. It sometimes idles irratically and changes speeds very quickly (a change of about 100-150 RPMs) when you stop. It rarely stays at one idle speed for more than 1-2 seconds when stopped. The RPMs most of the time drop to 400 for a second just after you stop, then start the up and down idle. The idle can smooth out, or it can keep going- its not predictable.

The high idle at startup is normal.

The rpms being high when not using the throttle while driving is normal.

What tuneup things have you done again?

Have you cleaned the MAF?

We just changed the idle are valve, and cleaned out the MAP and EGR, and checked the MAF. The PCV just got changed, and we changed the vacuum hoses. We had a P0107 code that now is out. I dont know if there is a vacuum leak, but I think so, so we are going to change the intake plenum and throttle body gaskets. But the truck did this long before the vacuum leak.

P0107 is for the MAP.

I dont know if any of this will help. I may have to take it in and have a shop do the high teck diagnostic machine. I just dont want to spend that much on a tech, when it can go for parts. Thank You.

Just make sure you do a COMPLETE tuneup before you send it to the shop.

We have tried alot of different brands of plugs, wires, cap, and rotors. Everything from AC Delco to Bosh, to Champion and right now Autolite. These plugs seem ok. It doesn't miss any more, but a little less. Cap, Rotor, and Wires are OE brand. Plug gap set at 0.060, as to spec. Put wire wrap and separators on just in case the spark was jumping.
MAF is spotless. Not a trace on it or in it, and no filaments are broken. K&N air intake kit.

Tune up:
Plugs
wires
Cap
Rotor
PCV
Cleaned air filter
Fuel Filter

Also Changed:
Ignition Coil
IACV
Cam-shaft position Sensor
O2 sensors
Vacuum Lines

Checked:
EGR (cleaned)
MAP (cleaned
Fuel injectors
Throttle Body (cleaned)
Intake Plenum (for cracks or build up)
Spyder Lines

You said that high idle is normal, but it can idle at 2,000 or more. Excpecally after its been started. The RPMs are not that high when driving 65 in fourth gear. They will surge when you put in the clutch, and this all started recently. Is all that normal? I've never seen one do this before. Expecially the irratic idle of 100-200 difference.

Spray TB cleaner through the MAF and clean off the filament wires.

K&N oil will cause the problem and really screws with MAFs.