acceleration/idle issue.Help

Hi everyone
Ok here is a story , i owe a 99 rodeo 4wd 3.2 90,000k i noticed a problem with a acceleration (not on the take off,take off is fine) .From a take off truck is going like holly hell but the thing is on a higher speeds like around a 40 mph when i step on it it hesitates ,feels like something holding it back(chocking) .Seems like it wants to accelerate but it doesn't i mean it does accelerate,but not as fast as it used too.There is no CEL.This is what i've done already.
New air filter
New spark plugs NGK's
New pcv valve
Cleaned Egr valve and a tube
Flushed tranny(thinkink that worn out fluid might be an issue)
Couple of days ago i went to a shop and gota fuel injection service done since thenmy idlle is higher, now on a 1000 rpm's and still no improvement on a acceleration:frown: :screwy:
Maybe somebody here had a similar problem and solved it ,any suggestion how to solve the problem will be greately appreciated.I know you guys heve a great knowledge about zu's ,i'm counting on you.

Thank you in advance.

Couple things, one you're right about the mileage for an O2 possibly getting sluggish; but I don't know if that would effect speed once you're already moving.

When 2 of my O2's were bad, it effected my actual take-off, not once I was to speed.

Also, may want to clean your MAF sensor, I've heard these can show wicked symptoms in relation to sluggishness, gas mileage, etc.

o2 sensors might be going bad without throwing an CEL?I will clean a MAF sensor tonight and report back on the outcome .Thanks so far

just a thought....

it sould be the drive shaft issue. a slight slippage may occur (or what feels like slippage)--it is the same thing that causes the "ka-chunk" feeling as you start moving. the 2 piece thingy is what i'm talking about....i know--very technical:rolleyes:

what plugs did you put in it? if you used the BOSH plugs that may be part of the problem. You should also bring it in to an exhaust shop and have backpressure checked, because if it has been running on the wrong plugs for a while you may have a catalyst problem. Good luck let us know what you find.

what plugs did you put in it? if you used the BOSH plugs that may be part of the problem. You should also bring it in to an exhaust shop and have backpressure checked, because if it has been running on the wrong plugs for a while you may have a catalyst problem. Good luck let us know what you find.

i used NGk's now but my prevoious plugs were BOSCH 4+.It's been few days after i did a fuel injection service and knocking on the wood i did notice a improvement in acceleration,maybe after a FJ cleanup a ECU have to adjust .Will go to check my exhaust some times this week .Thanks and will keep you posted

have you also replaced fuel filter

I will this weekend