Just for the record I have read A LOT of past posts on Hesitation....
97 Base Lude...All stock

On light throttle, sometime the engine will recieve NO gas for like a half a second to a second and then it come back to normal.

Guess what that does when your does 5mph, car stops and then leaps forward a second later making me look like an ***

Did:
Cap+Rotor
Wires
TPS
Cleaned EGR, IACV
Plugs- NGK platinum changed less than a year ago
Valve cover Gasket
Primary O2 Sensor

Any suggestions?

 

Does the car bog at all when you get on the gas or does it just sit there as if you never moved the gas pedal?

The car runs like it should other than that?

This only happens when you get on the throttle lightly?

 

Have you checked fuel pressure or replaced the fuel filter?

 

Have you tried seafoam? Maybe just clogged injectors not spraying properly.

 

did you adjust the tps or replace it?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JT &raquo;</TD></TR><TR><TD CLASS="quote">Have you checked fuel pressure or replaced the fuel filter?</TD></TR></TABLE>

x2 on the fuel filter

 

Did you clean the EGR ports on the IM or just the EGR valve? I also had this problem; unfortunately I don't have my car running yet, so I can't tell you for sure if the EGR ports were the problem in my case, but I know exactly what you're talking about.

 

Thanks for your responses ppl

Have you checked fuel pressure or replaced the fuel filter?
- I will be doing this shortly as I have also thought of that

Did you clean the EGR ports on the IM or just the EGR valve?
- I only cleaned the EGR valve, no ports done yet

did you adjust the tps or replace it?
- Replaced AND ajusted to 10% on IDLE

Have you tried seafoam? Maybe just clogged injectors not spraying properly.
- I did Seafoam last summer, so it hasn't even been a year yet

Does the car bog at all when you get on the gas or does it just sit there as if you never moved the gas pedal? The car runs like it should other than that? This only happens when you get on the throttle lightly?
- I kind of a mix of all those problems on part throttle: Slight Bogging, Hesitation. When it does do it (the gas cuts), its like I haven't moved the gas pedal (and yes my cable is ok)

WOT = No Problems (except I find my lude has less power that 2 years ago)
Compression Test = 215-212-200-215 (which is all in the 10% range)


I also ordered a new Knock sensor yesterday so I will see if that helps
I also saw a thread on the Egr port cleaning, that looks like a bitch to do

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jardolei &raquo;</TD></TR><TR><TD CLASS="quote">

did you adjust the tps or replace it?
- Replaced AND ajusted to 10% on IDLE

</TD></TR></TABLE>

10% whats that all about??

try the fuel filter... my blazer is doing the exact same thing

 

10% whats that all about??

Ooops.. sorry I was thinking about another setting. its ~.45 volts

 

might i suggest replacing the injectors/fuel filter, could be clogging. Had the same issue on my car, and Seafoam flush really helps, my 98 lude has been running smooth since.

 

How about too much slack in the throttle cable?
Maybe as you push the pedal its at a free floating spot where not change in throttle plate occurs.

It occurs when out of gear too? So if car is idling, you press gas pedal in a touch, no change in RPM for a couple seconds but than finally it raises? If thats the case I'd say fuel delivery, or a delayed spark. I would initially say its fuel delivery though. We need more info I think

If timing is retarded too much though you could have the same symptoms couldn't you?? (asking anybody from H-T)

 

How about too much slack in the throttle cable?
- There is no slack in the cable, checked numerous times. Cable is perfect

It occurs when out of gear too?
- Never actually tried that, but I don't think so

I also think its related to fuel delivery from what ppl have been saying. I will be changing the fuel filter tonight as soon as I finish work. I'll see if that solves the problem

 

So last weekend I change the fuel filter, and its not any better. Still waiting for the knock sensor and I think the problem is with my IACV even though I cleaned it out like 2 months ago...

 

Sounds like a bad TPS still. Do you have any CEL codes?

Is your MAP sensor old?

 

My TPS is brand new. I have another brand new one so I can maybe swap, but I was getting these problems with the original AND BOTH new ones so I pretty much ruled that out.

MAP sensor is original so maybe.....

But thats the problem: I HAVE NO CODES!
and its worse when its very humid outside

 

try adjusting your TPS to read 0.47volts at idle and see if that helps. If the TPS reads too low when your just barely on the gas the ECU will think your still in idle and cut the fuel if revs go over 2500 RPM.