ok, i tried searching...but with no codes i have little to go with.

my problem
occasionally from dead stop to accel i am getting a sluggish feeling, at first i thought it was the tranny on the way out. but now i am getting a weird surging at 2000rpm, almost like i am slamming the pedal repeatedly and then it stops. it happens on flat roads, hills, highway and street speeds.
at first i thought tranny/cruise control issue.
but i dont know.
like i said, no codes at all, no flashing lights or anything.

it just happens at random, engine warm or cold...weather warm or cold.
i cant find any reason to it.
i took it to a tranny shop, i went along with them while they test drove it with a scanner hooked up and got nothing. it happened while he was driving as well. only answer he gave me is he could do exploratory work, but we both thought that was bad for my budget.

any help is appreciated as always....sorry for being a little vague, but i have little to go on.

 

When was the last time a full tune up was performed? Sounds like you have an intermittent ignition issue caused by a spark leak from the wires or cap or possibly a problem with cap & rotor itself.

If you want to test for spark leak, park in a very dark area. Pop the hood and mist down the engine with a spray bottle full of water, engine running. If there is spark leaking out of the wires, you'll get an interesting light show.

 

i changed the cap, rotor, plugs, coil and wires when i did the lower intake job.
figured it had been at least 100k for those items, coil was original.

i will check tonight and report back what i see.
thank you for the lead (water bottle trick)

 

Might also check the TPS. Check with key on engine off. Back probe the connector and and check for 5v on the black and grey wire.

Then check voltage on the black and blue (middle) wire with the throttle closed..you should have 0.5-1.2v slowly rotate/apply throttle and make sure the voltage increases and decrease smoothly. Voltage should increase with throttle application and decrease when closing.

 

ok, check in time.....

frog, thanks for the tps lead....it checked out.
5v on first wire set
.5 to 5v on second wire set...moving throttle by hand current changed steadily.
was 5v on the high side for second wire set at wide open throttle??

swartlkk, sorry no light show...i checked all connections to dist, coil and so on. double checked plug wires for fit and possible broken wire. pulled plugs too. all gapped correctly and looking good.

cleaned maf while i was under hood.

all this done and still having the surging....whats weird is that it only seems to happen at 2000rpm... basically cruising speed.

still looking for things to look into.

thanks for the help guys.

 

TPS..sounds good. Just for giggles have you checked your fuel pressure while driving? See if it fluctuates with the rpm bounce. Could be a pump or regulator.

 

can do.
god i hope its not the pump, i just put one in last year, i think it was the whole package deal.

 

It could possibly be the torque converter clutch locking & unlocking, but that typically occurs around 1500RPM at around 45mph cruising.

 

ok, fuel pressure test within range...phew...

ok, i am thinking it might actually be a tranny issue....i smelt hot tranny fluid today..no leaks. dont know what to make of that.

i am gonna change the fluid/filter and take a look.
i am gonna try to test the solenoids. i dont think it is solenoid issue...still no codes.

to top it off with the colder mornings it is happening more in the morning...so it is temp related. once engine is warmed up almost never happens now...40 degrees and it goes off several times in a 10 mile trip.

i hate fumbling in the dark.....

 

Glad this thread came up. I've been having a very similar issue with my '01 with 115K for several months now. Seems like ever since I pulled a U-haul trailer back in May from Texas to Alabama I've experienced intermittent issues just as you have described. I've been trying to pin point the problem with no success. I get the sluggish most often when accelerating from a stop or even when going up a hill at highway speeds. I get the surging most often at these highway speeds of 70mph when climbing a hill just prior to the transmission downshifting into 3rd. A bit different then yours, I notice it most often in the heat of the afternoon but it depends on the day, someday's it acts up a lot more then others. On the highway at, If I give the pedal a relatively quick jab, the RPM with rise about 500-700, then immediately drop back below where it previously was with no acceleration while holding this new pedal location while some surging will usually occur. After waiting a few potatoes, RPM will rise and it will finally accelerate at a decent rate. If I tap the brake to unlock the torque converter, it seems to help but I still need to test that a but more to confirm. Also, gas mileage is pretty poor at around 15 MPG highway.

I haven't completely ruled out an ignition issue due to my blazer still having the original plug wires but I am also suspect of the torque converter.
Appreciate you keeping us updated on what you find out.