bogging no power off idle

i have been having this concern for awhile and looking for help. i can drive for awhile like 20-30 minutes s15 has lots of powewr . then starts bogging at part idle and if i just slightly off idle i can go upto 70 miles an hour. my s15 has a 4.3 vortec , auto trans with overdrive. i have replaced the fuel pump and filter and the fuel injector with the six lines and nozzles and new parts. i have duplicated the bogging in drive with someone holding the brake and me manually working the gas and have between 50-60 PSI on my gauge. i did a volume test and have 1 pint in 30 seconds. also if i turn engine off while this concerns is happening and restart it is ok for about 5 minutes then start over. overnight and i get the 20-30 minutes again and some times i get a few days before it happens again. when concern happens i have no codes and an oder of a lean burn exhaust. my OTC 4000 shows tps volts all the way up to 4.5V with no drop out and injection goes from 1.2 ms to 13 ms as though it is accelerating but it just boggs. and the temp and map sensors are all reading correctly. also the cat converter and complete exhaust has been replaced with all new parts. this is one of the strangest things i have seen can anyone help. thanks john:banghead:

1st run a can of seafoam through your system Then pull and clean your EGR with carb cleaner and a wire brush.....

If that doesn't fix it, look to plugs/wires/coil, but it does seem to be a clogged egr

what is seafoam, where can i get it and what does it do. also i don't see the connection with the LEGR as i have no hard brake peddle when this happens. please explain in more detail why you think the LEGR is having problems.my plugs and wires are new at this point. when concern happens i checked the coil output and have 40K volts. also the strange thing is like yesterday i limped home with this bogging and as i got close to the house it stalled ,i stopped put in park and it always starts right away. and put in drive and it ran like nothing was wrong. full power on accelleration. if there was a problem with the LEGR ,CPI,F.pump, spark plugs , coil why when it stalls and i restart it does it run great for about 5 minutes and sometimes for days. this is a crazy proplem. please give more info on the LEGR idea, thanks john or call 1810 891 9517 if you need to have me call you back due to phone charges i have unlimited calling, thanks again john

EGR not LEGR... That said, a clogged or poorly running EGR may not set a code, but it can cause bogging, and other poor running conditions symptomatic of what you have above... Because the pintle of the egr cannot open or close properly when defective or clogged, EGR gases are not thrown back into the engine properly if at all and the ECM gets confused on what it needs to do... A bad or improperly running EGR rarely causes a hard brake (actually I've personally never seen it cause a hard brake on either the vac or electronic versions)

Seafoam is an internal engine cleaner designed to remove carbon deposits. Seafoam prior to removing and cleaning the egr. 1/3 can in the brake booster line (pull the hose from the brake booster side) and pour in while the engine is running. Let sit one hour, then go for a drive till the smoke stops. Pour 1/3 in the crank case, and 1/3 in the gas tank..

After your drive pull the egr and clean it with carb or brake cleaner and a wire brush, make sure the pintle is moving freely. Look at the intake side of the EGR (egr port on the manifold) Pick out any thick carbon deposits. Chances are that some carbon will fall back into the engine. Run your engine while reving for a minute or 2 to blow out any loose carbon deposits that may have fallen back in. Reinstall your EGR... See if that cures your problem. It's a cheap diagnostic, but an important one to confirm or eliminate.

can i get seafoam at an autoparts store or do i have to go to the dealer

advance, autozone, and napa all carry it

Seafoam is definitely good stuff, it's solved many power\MPG related issues with my vehicles. When your engine "bogs" does it only lackpower when in gear? Or when it's happening can you slip it into N and will it struggle when trying to rev up under no load? Also it can't hurt to clean up your throttle body real good while you're in there as there could be alot of tar buildup from the years inside.

in park it revs up but in drive it boggs. and like i said if it boggs to the point of stalling and i restart it it runs get for a while then start to notice passing power disapearing then back to bogging. but stop put in park and cycle key and it runs great for a while again and never has hard starting, starts right away..
as for the LEGR i did have a problem a while back with hard brake pedal and hard starting then and there was a chuck of carbon holding the pintal open, cleared that out and new gasket and that was fine.that was about 8 months ago.
thanks for where to get seafoam i will try this. anymore ideas would be great just in case. thanks ,john

in park it revs up but in drive it boggs. and like i said if it boggs to the point of stalling and i restart it it runs get for a while then start to notice passing power disapearing then back to bogging. but stop put in park and cycle key and it runs great for a while again and never has hard starting, starts right away..
as for the LEGR i did have a problem a while back with hard brake pedal and hard starting then and there was a chuck of carbon holding the pintal open, cleared that out and new gasket and that was fine.that was about 8 months ago.
thanks for where to get seafoam i will try this. anymore ideas would be great just in case. thanks ,john

When it bogs, sorry for the repeat probing Q's, does it actually lose RPM (rpm drops from 2500 to 1500 for example) or does it just not get any higher (IE: you press the gas, it doesn't get any higher on the Tac and it just seems to not want to speed up?). I ask because I almost wonder if the lock in the torque converter is sticking on. That would explain the putting in park and cycling reseting it and why it only happens sometimes, and sometimes quick sometimes not. It wouldn't stick until you get up to highway speed and it engages, then when you decelerate and try to re-accelerate you will feel severely underpowered because it's not letting the tranny\engine slip or maybe even downshift properly. Try running it right up to about 50mph (80kmh) and let the OD and lock kick in, then slow down to 30mph (or about 45kmh) and see if it "bogs".

It would be like trying to accelerate in 4th gear kinda. Just another idea.

yes the rpm's drop out with the bogging. and when this occures if stopped at a corner then try to go i can go just off idle and anything after that it drops right on its face no power and no rpm's. is there away to disconnect the lock up if the seafoam does not work? thanks ,john
if you need more info you can call1 810 891 9517 or just post thanks

yes the rpm's drop out with the bogging. and when this occures if stopped at a corner then try to go i can go just off idle and anything after that it drops right on its face no power and no rpm's. is there away to disconnect the lock up if the seafoam does not work? thanks ,john
if you need more info you can call1 810 891 9517 or just post thanks

To cancel the lock in the tranny put the shifter into 3rd (or even 2nd to be safe). Usually the lock only kicks in (usually, I am pretty sure these trannies are the same) when you are in (D) with an overdrive option (or just a D = 3rd gear+lock). So forcing it to stay in 2nd or 3rd will eliminate the lockup.

Sounds to me like it happens when the system goes in to closed loop. Let me ponder on this a bit. What year vehicle is this?

this is a 1992 jimmy 4 door 4.3 vortec overdrive transmission. and when i accel from a stop when concern is current i can only accel just a touch off idle and it will go all the way to 70 MPH very slowly. you can hear the trans shift gears. but if you try to press the gas any further then a touch off idle it falls flat on its face and has a lean smell exhaust and acts just like you ran out of gas but it is still running but just barely. when you let the pedal return to idle it runs just fine. i also tried the other day to shift down a gear and still has same concern.thanks for any help ,john
parts changed so far CPI, fuel pump, fuel filter, plugs ,wires, rotor, cap, cat. converter, extention pipe, muffler, tail pipe, gas tank, ACT sensor, ECT sensor, MAP sensor.
correct temp readings on scanner.with in a few degrees abient cold.
no drop outs on TPS reading through full range.
fuel pressure during concern 54 PSI ( range 50-60 psi)
volume test 1 pint in 30 seconds.
no washing in intake.

When the engine is stone cold, (first thing in the morning, don't start it) connect your scanner. With the key on and the engine off, check oxygen sensor voltages, they should be zero. If not replace the bad ones. Check ECT and ACT voltages, they should be within 1 (or 2 at the most), degrees of each other. If not, figure out which one is incorrect and replace it. Next, have an assistant drive the vehicle while you ride along and watch when the system goes into closed loop. If the problem shows up immediately after going into closed loop, a contaminated oxygen sensor could very well be the cause. During open loop, the ECM ignores the oxygen sensors and inserts a "known" value. Once in closed loop, the ECM watches the oxygen sensors and the fuel trim circuits take over. Each time you shut the vehicle off and restart it, regardless of engine temperature, the ECM begins in open loop. To check the sensors, make sure the engine is at operating temperature idling steady around 1500 RPM with the system is in closed loop. Upstream, (before catalyst) sensor voltage should vary up and down between .1 and .9 volts rapidly. Downstream, (after catalyst) sensor voltage should remain steady around .1 or .2 volts. Post back your results.

the cold readings on the ect and act were 2 degrees apart.
i took the vehicle out for a drive with a driver while i monitored the scanner and fuel gauge ( hood was proped open to avoid pinching the hose). when the scanner went into closed loop the concern did not happen. but after about 10 minutes after closed loop it began when accellorating the trans would shift down and the rpms would go up and it would not get enough power to upshift, just like it was stuggling like not enough fuel . then i let off the gas and tried again to accel and it would fall flat on its face . when all this happened the first thing i noticed is the fuel gauge dropped from 55psi to 50 psi and never recovered. also the scanner showed O2 sensor while bogging 0.00 volts till pedal is returned to idle then it starts rich lean rich lean. and when the bogging happens the injector pulsewith goes to 13 ms as though it is trying to dump fuel to acel. and it still has the lean exhaust smell when this happens. i suspect the fuel pump as the gauge was steady 55 to 60 when the vehicle was runnig ok and dropped to 50 psi when bogging started. if the computer was the cause why would the fuel pressure drop. even though the pressure drop was not much i suspect i was losing even more in volume which i cannot set up a test to check when driving. what do you guys think. even though the pump is less then a year old i think i should replace it.

I am coming in at the tail end of this I know, fuel filter was replaced? Engine vacuum under load for possible cat blockage? In itself a bad o2 sensor would not have enough control over the mixture to make it bog down completely , certainly could lean it down to the point of hesitating ,but not a complete bog down. Just tossing some ideas into the mix, didn't read all the threads, so this may be old stuff.

thanks for your input max wedge , yes all of that has been done and covered so far. i pulled the tank today but now i need a gas tank as the old one is leaking . i went to the parts store and ordered a new tank and should have it tomorrow. i will post then . thanks ,john

O2 sensor showing 0.00 volts and injector pulse width at 13ms indicates that the ECM is in open loop. You can confirm that by watching "OBD status" on your scanner when the problem occurs. Try watching the MAF sensor voltage and TPS voltage the instant it goes into open loop. You may find something erratic there.

i replaced the fuel pump last saturday and been drive 100 every day now and have not had a problem at all . jimmy has its power back and has not skipped a beat. sorry i took so long to reply i just wanted to test for awhile to make sure. thanks for everyones input. it wasn't so much the 5 psi i was losing but i was losing alot of volume . i inspected the pump and sending assembly and have found no concerns on the old one. my guess is one of the pump impellors was locking up , this would allow pressure and could not get the volume without all impellors working. thanks john
old master you were very informative.
my back ground is 20 master machanic from michigan. this was one bazarre problem. but thats the kind that always come my way.

well its been a couple of weeks and still no problems . runs great and lots of power. just thought i would give an update.:)

well still no problems. running great. just an update