Hey guys I need some input here. I recently installed a 27" 2 1/4" dia. glass pack on my 90 f150 5.8. The original owner had already deleted the cat and had the pipe exiting before the rear wheel with the stock manifolds and y pipe and 2 1/4" pipe and a flowtech raptor turbo muffler . Before the glass pack install it was running fine, after I replaced the turbo muffler with a 27" glass pack she sounded great , but I never drove it around I just revved it up in the driveway cause there is no bed on it and its not registered so I never tested her on the road. About 3 weeks go by and I had to go up the street to turn it around so I could paint it in the garage, thats when I noticed it kinda bogged a little at light throttle and low rpm , and when I gave some gas it was fine. I was wondering if this could be because it doesnt have enough back pressure now, and maybe the original setup was at the max before there would be problems with back pressure. I wouldnt think the current setup would give me back pressure probs, its not like im running true 2.5 or 3" duals with headers. Could it possibly be from something else like maybe plugs or wires etc. she has been sitting awhile while I have been doing the body work and paint. Any one here have this problem before or is there someone who could shed some light on the situation before I remove the glasspack and replace with a muffler. Any help would really lighten the load of this overwhelming poor mans restoration. Thanks here is a pic of the glass pack below.

 

 

 

 

sorry I dont know why it was that big lol

 

I don't think you're having the Infamous Backpressure issues.....

Is the truck an Automatic? If so....I'd be looking into the fluid.....Possibly a fluid/filter change....

 

Yes its an auto, but I just changed the fluid, filter last year and it looks bright red still I also havent drove it in this time period either other then up and down the street a couple times. it also doesnt throw any codes. It just started doing this after I put the glasspack on which is wierd to me because it ran fine a couple weeks before, does the ecu have to relearn driving conditions when the exhaust it modified like this, I did reset the ecu by disconnecting the batt for 30 mins and reconnecting, but I dont think I started it or drove it enough times for it to relearn. Could it be the Ecu? I'm lost, it doesn't make sense to me why its doing this right after the glasspack was installed. Just curious, why would the filter and fluid make it do this? Is there anything else it could be?

 

It kinda feels like its running off only 5-6 cylinders at light throttle but runs good when giving it quarter or more throttle. Almost like it doesnt have enough back pressure to give me enough torque to get going kinda feels like it struggles a bit to get going.

 

Please resize or delete the picture you titled "the beginning" or this thread won't get much answers, scrolling sideways to read is extremely annoying.

 

I agree until Post #5 is re-sized or REMOVED... I refuse to bother reading this mess......

 

LOL, it's not back pressure (or lack thereof) Start by pulling codes, how old is the gas?

 

the gas is fairly new I put some stabilizer in it also. I didnt think it was back pressure thats why I'm asking what it could be. I'm not a mechanic, I suck at diagnostics unless I dealt with it before, its just weird it happened right after the install.

 

Have you pulled the DTC codes and checked the timing?? What is the fuel pressure?

 

this^^^

Back pressure is a myth

 

Guys....Simple thought....FUEL FILTER....If its been sitting around pretty much.....And has some old gas...Could be just a simple filter.....