96 chevy truck

davef

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Hello,

I have a 96 chevy truck with 350 cid and 130k miles. I have recently notice a cruising speed hesitation that comes and goes very similar to the 95 GMC posting earlier. The engines had new plugs wires and cap about 10k miles ago, new fuel pump and filter about 20k miles ago. When I am cruising at 60 to 70 mph (with and without cruise control), I sometimes notice a hesitation or jerking but very subtle. I have had the service eng light come on and had codes P0-133 and p0-155 concerning the two of the O2 sensors. Sometimes the light clears itself, other times I clear it but no other codes. I am wondering if I am having an issue with my injectors or am I having tranny issues. I have not noticed any decrease in fuel economy and cannot tell by watching the tach for any changes when the hesitation occurs. One other test I did was to set the cruise at 60 mph and down shift into 3rd gear. The hesitations were more noticeable since the rpm's were higher but still no change in the tach. Any help will be appreciated. Thanks.

Dave
 

Transman

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You didn't mention if you were throttle body or "Vortec" engine. The vortec has the injectors and pressure regulator under the plenum and are both notorious problems. These engines are upgradeable to "Real fuel injectors" adding performance AND fuel economy. You need to look inside the plenum, there are several ways including looking down the throttle bore. Look for excessive moisture inside or even liquid (fuel), this is a sign of a failing/failed pressure regulator and if so would be the time to upgrade the injectors. The kit comes right from GM, injectors & regulator. If you are at all handy you should be able to do it in an afternoon with no problem. I can post the part numbers if this is your case. Transman
 

davef

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Sorry I forgot to mention it is a Vortec engine. Yes please post the part numbers for the injector/regulator. I will try to look down into the plenum today. One other question, does the intake manifold have to be removed to install the injectors? I'm just thinking, it may be time to replace the rear and front RTV bead caulk GM so cleaverly used to install the manifold. I've done that job once about 5 yrs ago after it failed then. Thanks.
 

Transman

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You may wish to remove the intake but not necessary for the injector/regulator kit. Good Luck, Transman



The part numbers are as follows:
12568332 Assy. V-6 Fuel injector kit
88894355 Bracket (may come in injector kit)
17113215 Seal kit (does come in injector kit)
93441235 Assy. V-8 Fuel injector kit
93442096 Bracket (may come in injector kit)
17113206 Seal kit (does come in injector kit)
 
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