My 1988 GTA 350 (motor has 8k on a .020 rebuild with a ton of work), and a new 700R4...

Car ran great, then I decided to pull the smog air pump and tubes since the cat was gutted by the previous owner. Had a heck of a time getting the pipe out that goes around the back of the engine. In hindsight, I should have just left the thing. First thing was it threw a code 13 and stumled bad at like 45mph and low throttle. WOT it is fine, idles good. New O2 sensor, and it fired a 33. New MAF, new TPS, new ECM, and no more codes. New plugs, wires, cap, rotor, fuel filter, and it still hesitates. Sometimes. Very intermittent. Fuel pressure is like 30 at idle and 40ish at WOT. Need to tape the pressure guage to the windshield, but I am not thinking that is the problem. What could it be? Any ideas at all???? Almost acts like it is running rich at anything other than full or at least close to full throttle.

I may have to defer this to a shop, but hope I can figure it out on my own.

 

check your timing if you haven't already, I've accidently moved the distributor pulling that tube behind the motor before

 

Timing is 7deg, TPS is set right, and idle is pretty much dead on....

 

Check the 2 sets of wires going into the dist. Could you have knocked them out or bent them?

 

They are in for sure. I am ASSUMING they are intact.... My next step is to yank the distributor and verify each wire in the harness is still intact. Really didn't want to do that, but I am running out of guesses...

 

Here we have a problem. When you remove the hose to the FPR it should be around 44 psi. Could you have a bad regulator? Clamp off the return line and turn on the engine without starting it and see what you get. then release the clamp and see if it quickly bleeds down.

 

It could be, by why would that have conveniently happened when I yanked the smog stuff? Too much of a conincidence, but I am for sure going to check that out......maybe new runners since I have to pull the plenum to do the regulator (I think I do... have not really looked that hard...)

 

Assuming your filter is good and there are no leaks, there are 2 reasons for low fuel pressure. Bad pump and bad FPR or both.

 

That assumption I can make. I thought maybe the bad gas thing, so I replaced the fuel filter, and did a tune up. Then, a week later, replaced the filter again.... I will test the fuel pressure as soon as I get a chance. Thank you for your suggestions!!!! Anyone else, holler!!! THANKS!