Okay so i took the truck to go to the store and on my way there i got on it pretty hard. I noticed at full throttle the truck was surging and not gaining rpms after 4000 or so. Then on my way back me and a camaro was playing around and it done it again. So i then stopped and done a burn out. During the burn out the engine had no power and acted like it was going to cut off. So then for the next mile i had to pat the gas to get it home. If i held the throttle steady it would almost die tll i pated the gas again. After getting it home i got brake cleaner and sprayed the intake all around. There was no increase or decrease in idle when spraying the intake. Then i was standing there looking and thinking and heard a pop between firewall and intake and the truck started running finee. So my question is what does it sound like more a fuel problem or vacuum leak? Im up for any suggestions and thanks in advance.

 

Ya possibly low fuel pressure or vacuum leak. Any Check Engine Light codes?

 

No the CEL never came on. The truck has 141000 miles. When i changed the water pump the front of the motor was covered in a thick coat of black build up. I cleaned it all off and have kept a check on the oil and it hasnt lost any. Only drive the truck at best 30 miles a week. Its more a weekend warrior.and the motor dont look to have ever had anything done to it. OH and when it was acting stupid i did hear it pop back through the intake while getting it home.

 

Also this past weekend i took the TB off and cleaned it and IAC very good.

 

Also before all this started then at idle hit or cold the engine lopped like it has a cam and shakes the truck. Could it possibly be a worn timing chain also? The guy i bought it from had just done plugs, wires, cap, and button. Champion plugs btw. What are the common problems for the 5.2? Also has MSD blaster coil.

 

Today im going to try and check the fuel pressure but my concern is that right now the truck is running ok. So if i check the pressure and its good i really cant rule the fuel system out. But from experience ive never seen a electric fuel pump give a intermittent problem. Either it works or it dont. Also what is the best way to check the vacuum on the entire engine. I have a vacuum gauge tester but its for the old carburetor engine's. Will it work to test the vacuum on a MPI engine. If so where would be the best place to connect it for the testing?