Misses Hesitates ???? not sure

[Beach Tahoe 30]

Hey whats up guys.. my truck has been well mantained by me. It has 167000 on it i rebuilt the top end last summer all tune up items are new wires plugs cap rotor fuel and air filter. When at idle it has a studder almost un noticed.
when driving at a moderate rpm 1300-1600 no matter 45mph or 65 at this paticular rpm it stutters like its starving for fuel or spark not sure.. I did put a fuel pressure reg. in it today no change replaced all gaskets on the upper plentum there is NO service engine light .. so im stuck............I am new to the site and have a great deal of repair know how an would be glad to help anyone out

98 Chevy Tahoe 4 x 4 5.7 vortec

 

[lilsolo68]

dont know if this is any help but, mine acts similar to what you described except im pulling trouble code p0420 which has something to do with the catalyst system. i used a wooden stake wrapped with a towel and knocked on my catalytic converters. they both rattled as if they had rocks in them but one rattled more than the other.

does your rpms go up and down like crazy on the first cold start of the day? mine does and sounds like someones inside pressing the gas pedal every other second.

 

[Rivieraracing]

Have you both cleaned your throttle body and MAF sensors lately?

 

[matt14]

Clean the throttle body and re-check. Also try and take a fuel pressure reading, since you stated it feels like its starving for fuel. Has this started since you performed the tune up?

 

[Beach Tahoe 30]

New Cadilac converter an flow master.. I did run this stuff in the tank called sea foam it a injector cleaner made no difference the throttle body was cleaned when i put the Fuel presure regulator in yesterday MAF or mass air flow how would someone clean that ?????i have the k & n filter setup the cone stylebut again NO Service Engine Light ....

this problem is not a result of me working on it or any modifications this just started out of the blue 3 days ago prior to that it ran great

---------- Post added at 07:09 AM ---------- Previous post was at 06:57 AM ----------

also if you drive it hard i.e. get on it burn rubber it runs perfectly fine this problem only occurs when driving at a moderate speed in relation to 1300 to 1600 Rpm

 

[lilsolo68]

well i decided to go do some troubleshooting myself. first i replaced the plugs and wires because i kept getting cylinder 1 and multi misfire. then someone suggested an intake leak, well i bought a cheap granatelli intake from here and an adapter piece had a huge tear in it so i just went out and bought the autozone intake(speed by spectre). now my early morning start-ups are alot better, no more way up/way down rpm idling. it still stumbles after warm-up and im still getting the p0420 code. maybe later ill pull the o2 sensors to check for failure......did you get yours fixed, maybe you should check your intake/exhaust for a leak somewhere. before mine got this bad it didnt throw any codes but it did idle bad.