Hey guys, i have a problem that i have no idea what it is so heres some history first. Truck is a 99 5.9 4x4 quadcab with 88K on it. Was owned by a 42 year old women and taking to dealership for routine oil changes etc... I purchased it last year and have sense changed all fluids, 2" lift all around, 285MTR's and thats about it until recently. The truck never got good gas milage but hey its a truck but i was gettin 8ish...all city but i dont ride it most of the time. Well finaly one day after i took a corner the truck just basicly died.....would only idle and if i gave it gas it chugged on me....turns out COMPLETLY clogged cat...well runs MUCH MUCH better now that i replaced it except for the current issue which i have no idea what it is....here are the symtptoms..... About every 4-5 take offs i give it gas and it hesitates...engine doesnt really rev at all and then all the sudden.....Somethings "cathches" and you take off. I thought it might be the torque converter/tranny issue but ttthe fact that the engine isnt reving throws me off.....its not like its even trying to rev! so i dont think its starved for fuel/air. Anyone have any idea whats happening....P.S it only started this after i replaced the CAT. Almost like a rEally bad turbo lag but more of a jolt when it starts to go...and the engine isnt reving at all

Thanx for help and sorry its vague..

 

Sounds like a possible issue with the Throttle Position Sensor. If it's bad it may not be telling the pcm that the throttle is opening right away. You can get one at most parts stores, it takes 5 minutes and a torx screwdriver to change it. Wait for some more opinions, but this is my guess....

 

well with the clogged cat... you can have more problems then just a sensor... when the cat was replaced were the 02 sensors replaces as well? if not the 02's can be bad also from the heat buildup from the cat being clogged ..especially the forward sensor... throwing the PCM some messed up readings and hte PCM trying to adjust the timing and injector pulses accordingly.. any CEL's? also with a clogged cat you could have burnt up a number of components in your motor from extreme heat buildup... ive seen and heard of a backed up cat turning headers WHITE hot..almost transparent.. and burning valve seats....cracking the heads REALLY bad... our motors are known for cracks between the vavle seats and walls... but if that kind of heat built up..could have warped the hell out of the heads. or cracked the heads in a more severe case... its hard to tell what actually is causing the problem..but in most obviouse casses..wait for more responses on the thread and start with the least expensive and most sensable option. also with an exhaust system not opertaing properly...you culd have fouled out your plugs badly... easy to check..take one out on each bank and check them for burns or unusual charring... try repacing them along with cap rotor and wires wouldnt hurt either... goodluck and defenatly post back your findings and fixes for others to use