Stumbling at highway speeds

[pikappkaz]

14.15 volts when running, not a battery issue.

[rhandwor]

If it occurs on a hill I would suspect the EGR valve sometimes to much flow will cause this problem. After market EGR valves will cause if the proper shim isn't installed for this engine.

[pikappkaz]

Wouldn't the EGR throw a code if it was having issues? I could be wrong there, no idea. I'll take a look at it.

Does anyone have the wiring diagram for the fuel pump? I'd like to test some other points just to be sure, still baffled on this one.

[pikappkaz]

Anyone have any idea if the threads on the fuel filter are the same as the valve on the top of the fuel lines (where you plug in the fuel pressure valve? I still have low fuel pressure, so I thought that tapping in at the fuel filter and checking the pressure there would help to narrow some issues down. Is there any issue with doing this? I have no idea other than a clogged fuel line at this point, it is definitely a fuel pressure issue though.

[j cAT]

Originally Posted by pikappkaz

Anyone have any idea if the threads on the fuel filter are the same as the valve on the top of the fuel lines (where you plug in the fuel pressure valve? I still have low fuel pressure, so I thought that tapping in at the fuel filter and checking the pressure there would help to narrow some issues down. Is there any issue with doing this? I have no idea other than a clogged fuel line at this point, it is definitely a fuel pressure issue though.

with the fuel filter match the threads to your fuel gauge ...this is a different thread...

at the store they may have adapter...

[j cAT]

Originally Posted by pikappkaz

Anyone have any idea if the threads on the fuel filter are the same as the valve on the top of the fuel lines (where you plug in the fuel pressure valve? I still have low fuel pressure, so I thought that tapping in at the fuel filter and checking the pressure there would help to narrow some issues down. Is there any issue with doing this? I have no idea other than a clogged fuel line at this point, it is definitely a fuel pressure issue though.

on you fuel pump....,what was the part number ????

[pikappkaz]

The fuel pump is P/N FG0088

[j cAT]

Originally Posted by pikappkaz

The fuel pump is P/N FG0088

the 88 is for the 2door tahoe 5.7L

the 89/90 is for the 4door tahoe...5.7L...

[pikappkaz]

I have a 2dr tahoe, so this is the correct fuel pump. I had to trick the dealership into telling me the correct part number per the VIN so I could order it elsewhere for half the price.

[j cAT]

Originally Posted by pikappkaz

I have a 2dr tahoe, so this is the correct fuel pump. I had to trick the dealership into telling me the correct part number per the VIN so I could order it elsewhere for half the price.

usually rock auto has the gm part numbers..

[cjttmyers]

I had the same issue on my '99 Yukon. Ended up being the distributor. The bushings were worn out and the shaft would move around at high speeds can cause the miss. Put in a new one and no more problem.

[pikappkaz]

Any idea if there is diagnosis I can do on the distributor? Can I pull it and check the play manually? I'd really like to just throw one in there and find out, but I've already spent a ton on this problem

[cjttmyers]

Unfortunately I found out the hard way. It finially got so bad it messed up the cap and rotor button, then it would not run at all. So I had it towed and the local shop changed the distributor. They are the ones that told me about the problem. They told me they used plastic bushings and that it was a common problem.

I do not know if you can check to see how much side play you have in the shaft. The only code I ever got from mine was a #3 cylinder miss. The problem did get worse over time and it took well over 2 years to finially die.

Like you, I spent a lot of time and money trying to find the issue. I finially gave in that I would have to take it to a shop. I just never set up a time to take it. I guess it set up a time.

[pikappkaz]

Well, I managed to jack up the timing. Looks like a job for tomorrow. Any tips on how to get #1 to TDC? Pull all the plugs?
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[j cAT]

Originally Posted by pikappkaz

Well, I managed to jack up the timing. Looks like a job for tomorrow. Any tips on how to get #1 to TDC? Pull all the plugs?
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#1 cyl up and distributor rotor at #1..mark wires///measure wires any way just to be sure there good with ohm meter..

with the bearing bad I would expect a new cap/rotor to not look new anymore..