lack of power

htseat2000

Original poster
Member
Jan 25, 2013
62
I have an 89 Chevy Silverado 7.4L 454 dually extended cab one ton that I got from my grandpa's estate a couple years ago. it only has 77,000 miles on it and is fully decked out with running boards, heavy duty towing package, rear spoiler, front air dam and visor, and swivel bucket seats. love driving this truck, but recently I have noticed it lacks power, and hesitates on the lower end of the power spectrum till it is warmed up. still does it a little bit after warmed up but not as bad, but lately the hesitation has been getting worse. I did get a service engine soon light once in the past couple of weeks and it said 02 sensor, so I changed that, but it is still stumbling. any suggestions?

last time I drove it was a week and a half ago because alternator went out. I am wondering if that is some of the cause of the hesitation because I have noticed the last couple of months that the volt meter gauge on the truck has been hovering at 12 volts when warmed up and has never come close to the 14.1 volts.

any help is greatly appreciated.
 

RayVoy

Member
Nov 20, 2011
939
The voltage (at 12 volts) is probably not the problem.

I suspect a maintenance item, something like needing new plugs, a dirty fuel filter, or maybe a dirty air filter.

Do you have any info on last time a "tune up" was performed?
 

htseat2000

Original poster
Member
Jan 25, 2013
62
RayVoy said:
The voltage (at 12 volts) is probably not the problem.

I suspect a maintenance item, something like needing new plugs, a dirty fuel filter, or maybe a dirty air filter.

Do you have any info on last time a "tune up" was performed?

here is what I performed so far. I did this last summer already. I installed new plugs, new wires, new rotor and cap, new coil, new distributor, and new air filter. I installed a new fuel filter last month.
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
A couple of bottles of injector cleaner may help.
 

htseat2000

Original poster
Member
Jan 25, 2013
62
triz said:
I would hit the usual suspects. MAF, clean the throttle body and drop a bottle of AMSOIL P.i. Performance Improver Gasoline Additive

throttle body looks very clean. no build up whatsoever. I always burn 89 or 91 octane gas in it too. I may try the amsoil stuff, but I have put fuel system cleaner twice in the last few months with no change. will change the MAF sensor, but I am going to change the fuel injectors, EGR valve, IAC valve and fuel pressure regulator to see if that helps.
 

RayVoy

Member
Nov 20, 2011
939
htseat2000 said:
I am going to change the fuel injectors, EGR valve, IAC valve and fuel pressure regulator to see if that helps.
That's an expense way to TRY and find the trouble. Sometimes, the cheapest way is to see a professional. You don't have to have him fix it, just get a proper and correct diagnosis.
 

htseat2000

Original poster
Member
Jan 25, 2013
62
RayVoy said:
That's an expense way to TRY and find the trouble. Sometimes, the cheapest way is to see a professional. You don't have to have him fix it, just get a proper and correct diagnosis.

well i would do that but anywhere around here charges 100 bucks just to look at it.
 

triz

Member
Apr 22, 2013
746
I wouldn't change the injectors. You can try witchhunter. They do an excellent job at cleaning injectors. I think it takes about a week turnaround.
 

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