1999 Gmc Suburban no power after half throttle have to start vehicle with starting fl

[MrOrange]

So i have an issue with my 1999 suburban that is hard to get an answer on

So the burb has had this issue since ive owned it
I have to use starting fluid to start it when its cold
it has no power when accelerating past 30%
backfires back thru the exhaust

so far i have replaced the following parts

used intake assembly off of a running 5.7l
new direct fit cat and new 02s
new fuel pump , not sure if filter also was?
good working , maf , air temp sensor and igniter.

im thinking the engine is running to lean or too rich which would explain the no start with out starting fluid (lean) , or the engine is running too rich and backfiring thru the throttle body . not sure if ineed to replace the spiders or not?

[kwmech]

The fuel pressure regulator is part of the spider assy. Did you get a quality pump or a chinese pump from Autozone

[b454rat]

Cap n rotor? My yukon was doing something like this. Would idle but wouldn't rev, wouldn't start on its own, but would sputter with starting fluid.

[cadillac_al]

any codes?

[MrOrange]

So power loss at 1/2 throttle , seems to run fine otherwise. Not sure on the fuel pump was installed before vehicle was purchased.

It did have multiple codes for the cat on b2 and o2 sensors. I monitored the cats on my solus and they were shot, but i think that they failed due to the engine running poorly( too much fuel , not enough?)

My only reservation with changing the injectors is they are moderately labor intensive and expensive for just an educated guess.

I wonder if the fuel filter is partially clogged ??

[AussieinNC]

I would change the fuel filter, then drain the old one into a plastic container and look at the residue...

I know of several full injector renewals all due to clogged fuel filters...

Simplest first step....

[biketopia]

Make the sure coolant temp sensor in the intake isn't broken or failed. If it's failed it will think it's -45 out and dump a ton of fuel in it at cold start. Also when the intake was changed, was the distributor set 100% correctly. You have to sync it right using a certain procedure and scan tool, can not just hook a timing light to it and go. The cam sensor is built in to the distributor, had issues with those before.

My dad has a 98 that was giving a misfire and he wasn't near home for me to fix it. He took it to a shop where he was and they put in an injector spider. After that the truck still had a hard start at times and random misfire at steady cruse occasionally. Re-synced the distributor and set it where it was supposed to be and it ran better than it ever has. I'd check those two items and watch live data at cold start to see what's going on before throwing more parts at it other than the fuel filter.

[MrOrange]

I have a solus ultra scanner , and the temp does register correct temp. I didnt think about the dizzy being off to see if its off. i will check that next

[b454rat]

If the dizzy is off the check engine light will be on. My 98 Tahoe had the light on for timing, was off bout an 1/8 maybe 1/4" at the cap, buddy barely turned it and went off. It didn't make any difference power wise, but hate having the light on lol.

[biketopia]

They don't always tell on themselves, my dads truck wouldn't always throw the light.

[gvw5400]

Can you check your fuel pressure?
I had a 96 S-10 with a SCPI 4.3 that would not start without a squirt of either.
Fuel pressure was 4LBs under spec. What was weird is it ran fine once started.
Changed the pump, and everything was normal again.
It seemed strange that 4 PSI. made such a difference! It would Rev and pull strong
in any gear, (5 spd.) just wouldn't start.
All the Best
Dirk