98' crappy take off bog with AC

when ac is on, on my 4.3l 98 blazer.. it sucks ... it seems to switch gears differently it feels like it bogs and take offs are sluuuuuuuuugish .. but when AC off it seems to be ok for the most part ... this blazer is super clean... had plugs checked ... they are fine ... only thing i think could be wrong is the cap and rotor ... when raining it seems sluggish to .. could the moister from AC be getting under cap/rotor ??? today i noticed my battery gauge was not in the center either ... when idoling it was half way between all the way left and center ... not sure what the number is ... could my battery have anything to do with it ???

any suggestions ... i drove another blazer of my friends the other day and that thing could smoke mine and its stock ...

no ticks, knocks, anything just sluggish ...

slight vibration that goes in and out when idleing .. with AC on or off ...

What milerage?
How is the tune up end?
How is the fuel pressure?
Any check engine lights or codes?
What is the key off and battery charging voltage ?

145,000
got plugs checked last month still good
just got new fuel pump and filter.. around 58-60 i believe
no codes no check engine ...
i guess ill go get the battery tested this afternoon ...

um not sure about the wires .. but tonight when it gets a little darker im gunna go outside and spray some water over them and see if i can see any sparks ??

should i just use a hose and my thumb or should i use a squirt bottle ...

which would work best??

and how do you see if your wires are glowing ??

when im driving sometimes ill feel it acting sluggish(like running on 5 cylinders) but will keep the thottle still and after a couple of seconds it feels like it hits all 6 cylinders again and picks back up ...

Fuel pressure is low.
Specs are 60/66.
On the wires if that many miles replace they.
Do not wait for them to jump out from under the hood to bite you.
How many miles on the plugs?
Good Ac-Delco plugs?
A good engine capable scanner will record the missfires and tell you what cylinders are missing and how many time.
Low fuel pressure or camshaft retard setting off will also give a missfire.

Battery voltage can be checked with a volt meter.

Did you replace the fuel pump with A Ac-Delco/delphi or one of the junk airtex wonder if the may run pumps?


A quick test is to block off the return line and see if fuel pressure comes up to 75-85 lbs.
But do not run the pump at full pressure very long.
Also when testing fuel pump and pressure you need to tape a gauge to outside windshield or outside mirror and drive it on the road for 20 -30 minutes
until the pump gets has run a while to check for a pump fading out after hot.

Hard to start cold or hot and fuel pressure testing guide lines.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak in system.
Post back fuel pressure readings.