I am having a problem with my jimmy when you drive it 10-15 min or so. At 3/4 to WOT it boggs down really bad. And the more you run it the worse it gets. The funny thing is if it starts to act up and you pull over and cut it off and let it sit for 2-3 min it will start right up and act like nothing ever was wrong and run fine for 10 min or so. I started out thinking it was a fuel problem because these things are known for the CPI's to go bad and it DOES NOT have a SES light on.So I replaced the fuel filter and the CPI unit and still the same fucking problem.Also about 2 mo. ago the fuel pump went out in it so that was replaced also with a new unit. Also we hooked it to a diag computer and everything is showing a ok. I am lost with this fucking thing. Also I checked the MAF and it checked out ok and I replaced the map sensor and still not fixed. Any help would be great!

 

I remember reading someone having the same problems on http://www.blazinlow.com/forum/

if you can't get a quick answer here...look over there. Also, you'll find other good shit over there for your jimmy.

 

Thanks!

 

Bad plugs and wires can do weird things. I would replace those with a good set, not the cheapest you can find. Many times, OEM is far superior to alot of aftermarket because they are designed to last 100kmiles. About the only thing GM doesnt skimp on.

 

were did you get the new fuel pump? Have you took the scanner for a ride to record the data while the vehicle fucks up?

 

found anything on this?

 

My guess? Collapsing fuel line. . . does it have an in tank pump? Has it sat for a long period of time?

 

How many mile are on your motor? Sounds like you are having a similar problem to what I had to go through with my 96 Blazer. I had to replace my EGR valve because it wouldnt hold an idle, I had to pop in neutral and rev the engine above idle RPMs.

Try the EGR valve. If it doesnt fix it, it needed replacing anyway.

 

hook it up to a scanner. check and see if the timing is retarding when it bogs down.

 

How much gas is in the tank? Did you install a new pick up, in the right direction, and so it would stay on? Are the fuel RTN and vapor lines hooked up right and tight?
Just a few ideas.