fuel sending unit/fuel pump

[Dneel81]

1997 2 door tahoe. 198000 miles
Replaced pump (EP381) and fuel sending unit (FLS1069) because of the loud noice the pump was making
and a new (last 300 miles) lurch while at speed and the fact that my fuel gauge quit working.
All went well, fired her up and she's still lurching at cruise. Just for a moment, the engine stumbles and then gets going again. It's only long enough to be noticeable.
What are the odds it's the fuel relay in the fuse panel in the engine compartment?
I'm usually not a fan of throwing parts at a problem but this is the only other thing I can think of.

Thanks

and yes I searched and confirmed a paucity of information about the 2 door issues. Read about the 4 door issues and this seems like the next logical step.

 

[Rocket Man]

Not sure on the 97's but on the 00-06's there are several of the same relays in the fuse panel. If so, try swapping a pair to see if the trouble follows the relay. It's a free diagnosis.

 

[Dneel81]

Got the fuel relay replaced and she does not stumble except after about 5 minutes (warm up) and then it starts again. Forgot that I replaced the fuel filter also. Not throwing any codes other than the torque converter one (which it doesn't even have a torque converter anymore). Anyone with any ideas? Thanks !

 

[mizzouguy]

Ignition control module?
Coil?
Crank position sensor?
Trying to think of electronic things that dont like heat that could kill ignition momentarily.

 

[Dneel81]

I get my OBD2 reader back tomorrow. The CEL has been on since I swapped trannies. I'll make sure it's not bringing up anything other than shift solenoids and trans temp sensors that it no longer has. Thanks Shane.

 

[Dneel81]

And the saga continues..

multiple codes on the scanner. Most of them are because of the nv4500 in place of the auto 4L60e. Non-transmission related codes are as follows...


P0102 - mass volume air flow - low circuit
P0340 - camshaft position sensor
P0441 - evap emission system-incorrect flow

I was fiddling around with the air intake jazz. Took out the air temperature sensor. the idle that was erratic went away immediately. Drove it, let it warm up, and the lurch was gone. All good right, must be a bad air temp sensor. Bought new one. lurch is back, erratic idle is back too.

I did add coolant to the reservior. it's now gone. Thinking I have a leaking headgasket. Might have fouled the spark plugs with that maneuver.

I'm really trying to avoid throwing parts at this problem. I've wasted this $20 on the ATS today.
With regard to the above codes, I've read alot about them individually.
Seems the mass volume air flow - cleaned up the MAF and checked wiring. No vaccuum leaks anywhere that I can tell with a spray gun and alcohol.
Camshaft position sensor: can't say I've heard of anyone replacing it and it actually being the problem. I'm open to any suggestions you guys might have.
Evap system: I've checked for leaks and can't find any.

I'm not totally against taking it to a shop. I have yet to find someone reputable who's not looking to get into my wallet. I don't like being taken advantage of. If I can fix it myself, all the more god so I can learn too.

Anyone have any clues as to whats up ? thank you in advance.

 

[Rocket Man]

I had a random intermittent serious stumble for months. Sometimes at a stoplight it would almost die. Ended up being the MAF, and I had replaced it with a new off-brand one a few months back while chasing another problem ( which turned out to be plugged cats). I bought an AC Delco one and no more stumbling. I know you cleaned yours, as I did, but sometimes they just go bad. They can cause multiple problems.

 

[Dneel81]

Thanks Mark. I'll probably at least pull the spark plugs to see. If they're fine, I figure the MAF is not too expensive. The previous owner didn't do crap for this truck, really took poor care of it. At this point, most things probably need to be replaced anyway.

 

[mizzouguy]

If its eating coolant, maybe that's causing the lurch/misfire as well? I had a car that had a leaking head gasket, and it would run poorly on startup until the cylinder got cleaned out and then run great, so kind of the opposite as you. Stuff expands when its gets hot though. You may want to rent one of those leak testers with the color changing fluid first just to make sure its not a head gasket before you spend too much on other things. Most parts stores rent have them and you just have to pay for the fluid.

 

[willxfs]

Low engine coolant could also be the lower intake gaskets. Original OEM gaskets are known to go bad and leak.