99 Tahoe giving me a beating

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smackleboom

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Hi all let me start by saying never in my life I thought a Chevy could defeat me:sad72: I bought a 99 Tahoe a few weeks ago because the owner could not get her to run properly. It would start and idle ok but touch the gas peddle and it bogs, backfires,and barely goes above 1500 rpms.i read through these forums for a few days then I attacked. So far the previous owner had put in a new distributor with cap and rotor and a new fuel pressure regulator. I have put in fuel filter, spark plugs,front O2 sensors,new timing chain and gears, intake gasket,and did the camshaft retard to 0% at 1000 rpms. I'm using a Genisis Newvo scan tool, I have no CEL but a p0154 and p0300 is pending. I am almost 100% sure that I don't have any vacuum leaks. My only discrepancy is that the fuel pressure is at 52-59lbs (with new regulator being verified) and the previous owner had the cats gutted.othewise all of my engine sensors have normal readings. That being said ....I'm convinced that what I did,needed to be done I don't want to randomly throw parts at her so I'm crying for help even though it's better in the Bahamas......parts ain't cheap
 

lesterl

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1. Disconnect the Y pipe from the manifolds and retest.
2. Unplug MAF sensor and retest (or tell us what your reading is on scantool @ idle (lb/hr)
3. Distributor in time properly (I know you said you set it, but.....)
4. Crank/ Cam gear aligned properly, if a tooth off it can run like that....
 

smackleboom

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Hey Lester thanks a lot for your advice.........the culprit proved to be the spider injectors I put in a new set today MPFI and she's running at 98% :happy160: still have a slight hesitation every now and then but am still going to change out the pump tomorrow. Oh I did find a broken O2 signal reference wire (b2s1). But even after the repair am only getting the vcm generated value from that particular sensor and I have absolutely no codes generated......so am hoping that the fuel pump will get rid of the hesitation ......thanx again and I wil post my findings
 

lesterl

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Hesitation off idle? Test the TPS for smoothness (voltage), also check/ CLEAN MAF sensor. Fuel pressure test?
 
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