hesitation when engine under load!!
 

ok guys i am going to try to explain this as clear as possible! when ever i am driving and my car is under load, the car will begin to bog, like when i am in 5th gear 1,500 rpm and i give it some gas the shifter begins to shake a bit and the car will hesitate and it feels like there is no acceleration! but the top end is ok, it still pulls up top!! i have recently gutted my cats thinking that would be the solution but still dident do a thing!! but i remembr sometimes the it would bog like really bad to the point i needed to downshift to accelerate!! i recently also change my drivers side front o2 sensor due to po171 and po131 running to lean and low volts. i also changed the seal on the egr to intake pipe and my fuel filter was changed 6,000 miles ago!! i am going crazy and dont know what the hell the problem is!!! i was also recommended to change the passenger side o2 sensor as well to mak sure thats ok, but i will be checking my fuel pressure soon! to mak sure the pump is not the problem!! but please guys i really want to figure it out! i am not driving my car because i am angry bout the whole situation!! so thanks alot for any input!

Try cleaning your MAF. A fouled MAF sensor will cause a lean condition, which can lead to the hesitation and your O2 sensors throwing codes.

well i did clean my maf lik 5 times!! but as of now my car has not been throwing codes, eversince the bank 1 sensor 1 was replaced there has been no codes! but there is still hesitaion!! i am going crazy what the hell is the problem!!

i have also noticed that before when i used to open my engine oil cap, the rpm would go down a little! but now when i open the oil cap there is no differance, no change in rpm! does that mean i have a vacum leak???

I had the same problem. And it ended up being some bad gas that fouled up my plugs. My plugs only had 15k miles on them. And changed the fuel filter around the same time. Once I put the plugs on I also motorvact it and it runs like a champ now. Good luck!

thanks for the input man whats motorvact???? and i changed my plugs 2,000 miles ago!! but i was running rich in bank 1 and that may have fouled the plugs up pretty bad! i will change my fuel filter to see if it will help thanks tho for the help!

well if your in 5th gear and under load that that lower of a rpm, mb your gear ratio etc, mayb you just dont have enough power to pull you through, i think if i did that my car would bog too

well i see your point but my rpms is like at 1,500 thats enough, and it shakes when its bogging, and i can feel loss of torque too! it was never like this before, before it would pick up and just go in 5th

after i my header install i had a missing problem ended up being a bad plug wire the tab on my stage 8 locking bolt had grouned out the wire it ran decent a WOT but lower rpms ran like ass. could really see it arking at night time changed the wire and plug and bent the tab and she runs like a champ.

o hay guys i just found out i threw a code for cylinder #4 misfire!! po304 and i just got new plugs and wires so i thought it was the coil so i removed the wire and started the car and i saw a little arc only a few times coming from the coil pack!! do u guys think my coil pack is dead? or is it the new plug?

Switch it to a different cylinder and see if the miss follows it. Motorvac is a machine that plugs into your fuel rail and runs a detergent through your injectors.

yea im going to try to fix it tomarrow, but the motorvac would be an excellent idea!! i want to know where i can get that done to my injectors!! thanks for the info

Your welcome, just about any local shop should have one. Good luck!

yea thanks alot man!! i just pulled my #4 injector wire today and noticed the engine ran more erratic then normal when revved!!! so i think that illiminates the chance of it being an injector right???

Im not sure. Hook up a scanner and see witch cyl. is missing and then fool with that stuff.

yea imma just take it to the shop! thanks

the shop said that its my #4 coil!! because the hesitation is worse when its cold, and smothens out when it gets warmer! do u guys think the coil has got a little weak and lost its energy??

i talked to my auto instructor and he told me it could be also a cracked intake manifold! and he said a coil can definently get weak thats a possibility

A coil is either good or bad. I dont think its a coil. Maybe injector,or plug. Mine did the same thing and it was the plugs. NGK's are 15$ and its a cheep way to start.

wow well its hard for me to believe since my plugs are new, but it wont hurt to check! i hope i dont damage my new a.i.r gasket on the flange! thanks LS1crazy01