I have a K5 blazer that I swapped TPI into on a crate 350. I did the swap 6-7 years ago and it ran great at first, but for the last 8-9 months it has been giving me issues.

A little background on the unit to start, the intake is from an 86 camaro, the ecm is from a 92 corvette so I can run speed density, and the harness is from street and performance. When I installed the setup I got all new sensors, new accel injectors, and had a prom chip burned for it. I'm also running long tube headers with a heated O2 sensor.

About 8 months ago I got a code 44 and the engine started backfiring on deceleration, got a hesitation when moving from a stop, and also feels like it lost a lot of power through each gear. Another thing it's doing is when coming to a stop the rpm's drop down to around 400rpm and then go back up once stopped.

I fixed the code 44, by fixing a few exhaust leaks that I had, but I still have the backfire, hesitation, and no power. I've checked fuel pressure and it's got 42 psi at idle, just changed the fuel filter, new plugs, wires, cap, rotor, and coil. Checked for intake leaks around the intake base, runners, plenum, vacuum hoses, and throttle body, just haven't put a vacuum gauge on it yet. And I also just emptied out the 9 month old fuel and put a fresh 10 gallons in.

Any ideas on what I should be looking at next? This thing is starting to **** me off and I'm seriously considering a LS swap.

 

Timing move? Problematic injectors? Time to find a jy 5.3L?

 

For anyone that's reading, I fixed the TPI in my truck.

It ended up being 3 faulty injectors. I replaced them with Bosch D3 injectors from SouthBay and the engine runs great again.

 

Injectors can be a pain to diagnose... Glad you figured it out.