If plenums good and dirty,then its not leaking there. if you drop to 30 in 6 minutes,then the pumps leaking down. If you spend the money on a ac delco, you wont have another issue. You said the previous owners changed pumps,they used the typical aftermarket crap. this fuel system is simple. If the spider/reg isnt leaking theres nothing else to replace but the pump. Unless a lines leaking.

 

Well the lines are the next thing to check, but I don't think that would account for the on again, off again problem while driving.

 

I was finally able to drive the truck today with the fuel gauge on. It's gotten progressively worse, I can drive slow on surface roads, but not on the highway. It stumbles, sputters and cough with no power. I thought for sure that the gauge would show me the pump was cutting in and out, or at least the pressure was dropping.

Nope. She runs at a steady 50+ and when I accelerate it goes up to about 60. I thought for sure it would be dropping when it stumbles. Funny, I didn't WANT to change the fuel pump again, but if that was it, at least I'd have known what the problem was. Now I'm lost.

I don't know where to go from here. I pulled the EGR valve and cleaned it up when I had the plenum off, though it really wasn't dirt, so that's out. Not sure what's next.

 

ign coil not keeping up with the engine? check to see if it's heating up or have it ohm tested

 

As far as I know the original owner changed the fuel pump once or twice. My friend I got it from changed it 2-3 times. I replaced the tank, and had it down again to change the pump last year (apparently for no reason it seems).

Not looking to drop the tank yet again…. disgust, frustration, anger and a sawzall all met together at the same time a couple weeks ago.




I put a new Delco fuel pump and screen in in. Again, apparently for no reason as it isn't really running any different.

The other night I dropped the cat converter. Haven't had a chance to run it without to see if that changes anything. I hope so, but I doubt it.

Last year when it was doing what it's doing, I changed the coil and TPS because I had new ones on hand. Didn't help. Got angry and changed the spider, FPR and pump all at once. Didn't make it right, but it ran differently and finally threw a code. Changed the 02 sensor and it was good for 9-10 months. Now I'm back to square one.

The spider I changed last year was a rebuilt and only a year old. Did the nut kit at the same time, searching for the mystery problem the year before which turned out to be the module. Changed the pickup, cap and rotor while I was at it. (C&R since then as well) Fuel filter many times.

I've had a clogged EGR before, that's not it. I'm running out of things to change. If the damn W engine MAP sensor wasn't so much, I'd change that too just for the heck of it.



If I'm easy with the gas she's fine. But if I need to get on it, like to merge, she sputter, stumbles and farts.

 

have you checked to see what your ign timing is doing? and where is it set at?

However sounds like your computer might be bad

 

In all of these posts, you never say what year this thing is. By the looks of the pump, and mentioning a "nut kit", it must be mid 95 or older, (CMFI) and it looks like this?

 

Huh. It's a '94.


I haven't checked the timing recently, no, but it's not an all the time thing. (distributor's been replaced once and it is tight) It's not all the time, nor is it the same… intensity every time. Some times it just mildly annoying, others I have to pull to the side of the road because I'm holding up traffic. And then it goes away.

 

95 and before had the vortec with the CPI (which is shown in that photo)

 

Okay... now I'm really confused. (as to your point, did you think I didn't know that? lol )