loss of engine power uphill

I have a 98 Passport with 120 k miles. I just fixed my EGR problem by purchasing a new egr and a good cleaning of the intake. I passed inspection great. Now I noticed a lack of power on incline an addition a engine noise that sounds like marbels on excelleration only. I did do the following.
new NGK plugs, pcv, air filter, fuel filter, changed octain to 87 3 tank fulls now including a fuel injecter cleaner in the tank.I think it was the dectron? stuff for a twenty gallon tank. Computer light is off 400 miles later. she idils quiet. minimal valve noise, no air vacume leaks. any other suggestions?? oh yea im getting aprox 14 mpg city.
Thanks

possible MAf sensor issues or IMG issues.

if i read correctly, the CEL is on (?)--go get the codes read at autozone or advantage auto parts--(most auto parts store will do it for you now) and post back here what they are. the gurus that live in this place are wonderful (!!!)

I see you changed all the filters, but have you ever run a K&N type of air filter?

if so sometime the oil will coat the MAF.

I see you changed all the filters, but have you ever run a K&N type of air filter?

if so sometime the oil will coat the MAF.

i don't have a k&n filter installed (yet), but when i do, i found a special boot extention that has a sort of "ridge" in it that allows for the oil/ water/ whatever to drain down into there in case you get over-zealous with the oil--that might be a good idea

Originally I had the famous EGR problem which I corrected thanks to this great web site. I disconnected the bat cable for the CEL to reset. I drove the car for a few days without a problem and passed my emissions. How ever I still notice that bearing like pinging type noise on acceleration incline at about 2000 to 2500 rpms and than it goes away on cruising speeds, which don't require any real push on the vehicle so I don't hear any noise. I checked for loose exhaust pipes, shielding to confirm that it is not the exhaust.
What is the MAF. Can it be cleaned? Should I just change the the oil? I am using 10 w 40 but was planning on going to the 5w 30 I think thats what I read. My CEL is off 600 miles later.

As far as a IMG, I sprayed the intake to look for engine change, non was found. In addition no noticeable vacuum type leak on engine idle and acceleration.

It sounds like your 3.2 is leaning out under load. Like the other fella's recommend, if it's not a vac leak, which it doesnt sound like, check your mass air flow sensor (MAF). It's the assembly clamped into the air intake tube just downstream of the air filter box. They can be CAREFULLY cleaned with electrical parts cleaner & a GENTLE cotton swab if you can. MAF's can be a couple hundred bucks to replace.

G/luck
Joel

Thanks Joel. I'm going to try to clean it out at lunch time today. I'm also going to change the oil back to 5w 30 I read using the 10w 40 was not recommended. The truck is almost running as good as it did when I purchased it with 16 k miles on it. After the tune up I mentioned above. If I can get the noise out on acceleration Ill be very happy. I want keep my truck as long ass possible. Ill even consider purchasing a newer model. But this time with an exxxxtteeennded warranty. Ill advise on Monday on the MAF. Should I run the engine with the MAF off and spray Carb cleaner in the air intake while I have it apart??

I'd pull the MAF assembly out to clean it.

Joel

All done. Not to bad. No real sludge found on the hair like fibers. I sprayed them anyway with the electronic cleaner. The honey comb like mesh was OK as well. Found some minor dry particles. I cant tell if it fell in while pulling the sensor off the air intake housing or not. But I cleaned it. I find out how she runs at the evening rush our. Should I reset the computer by pulling the batt cable?

yes, might as well see if you can reset the codes and if the CEl will fire off again.

let us know!

OK the truck has more power without a doubt. She runs like when I first purchased the car at 16 k miles on it. How ever I'm still getting a ping like noise when I go uphill. Not as much. But it is still there. I looked under again. I did find a shield that was loose on th engine pipe the protects by the o2 sensor. The rest I moved around and I can simulate or detect anything loose. But I do have more power. I'm hopeful that tis will increase my gas mileage. I changed my oil to 5w 30 and I increased my octane to 89. Also no one in New York City sells fuel injector cleaner that goes in the fuel manifold. I guess I can try that. Any other suggestions?

I found the ping goes away with a quality oil filter. Try the Isuzu filter, Purolator plus one or the wix models. I found using the napa nascar spin flow oil filter works well, It is made by wix.

John

I never knew that the oil filter would have any thing to do with the engine pinging other than the oil breaking down causing the valves to knock etc. I did have the oil changed at local service location. But I'll give it a try.
Here is another clue I discovered last night after work. I did not warm up the truck to normal operational temperatures. As I got on the highway I had to rapidly speed up into a merge putting a heavy load on the truck. I expected to hear the famous pinging. It was not their. I continued to punch down on the pedal to get a load on the truck again. It would not appear. 10 mints later the truck reached the normal operating temp. The pinging came back on a load again. I driven 1000 miles now since I replaced and cleaned my egr valve which was my only problem. never had a ping. So is it possible that perhaps the egr intake was not cleaned completely in all the cylinders? Causing this ping. My CEL never came back on and passed emissions.

A theory is, these engines seem to lean out during certain operating conditions & have a *heat* problem within the combustion chamber(s). Hot spots can give you 'the ping'. You wont get any of this until the engine reaches operting temps. Some 3.2/3.5L ping like banchee's their whole lives while some rarely do. I think it's a mixture of ambient temps, barometric pressures, gasolines used, spark plugs used and maybe engine and sensor conditions. 1998,1999 3.2/3.5's have knock sensors, 2000+ do not, they rely on the ion sensing crapola. You could try a new set of denso, NGK or champion spark plugs, or changeout the knock sensor under the common chamber. Other than that, don't waste your money on premium fuel, just keep your EGR and MAF clean, keep up on regular maint, try different brands of gasoline and let her ping until she dies or you get sick of the truck! I've never heard of a 3.2/3.5 die from a ping induced meltdown.

G/luck
Joel

I had a pinger for 3yrs and 70k miles.

Resolution: Moving to a higher altitude. Seriously.

I bought the truck in Las Vegas, NV at 11k miles. Truck ran good, never an issue, except it would ping under even the slightest of load.

Took it back to the dealer NUMEROUS times - only answers they could give me -

1) was to try a higher octane (manual calls for 87) but I ran several tanks of 89 octane; not one single difference.

2) they could reflash the system (didn't know it then, but that meant to retard the timing), had them do that as well, still didn't change a darn thing.

Tried numerous different gas stations, 2 sets of spark plugs, ran Havoline 10w-30 oil with an Isuzu filter, didn't matter, she still pinged, and yet ran real good.

Happened to be we got a transfer back to Denver, CO and a quarter of the way through Utah on the same tank of gas from Las Vegas, the truck suddenly stops pinging doing 65mph at 3500rpm's with a 4k# load.

Thought it was the strangest thing, figured for sure once we stopped and cooled the engine off that it would start all over again.

Well it does, but ONLY at 2k feet and below to sea-level; has not pinged a single day in over 6yrs at higher elevation. I now have 153k miles with no obvious issues from having been a pinger.

Go figure.

Oh, but I do still have to run 87 octane, even though in the owners manual it states that in high altitude you can run 85. Not the case for this truck - I tried 2 tanks of 85 octane 2yrs ago, and the ping very lightly returned.

where is this knock sensor located on th eengine? What is the average price for this sensor?

Where is the knock sensor located on the engine? How much is for this item?

Threaded into the block valley under the common chamber. Will require removal of the common chamber (upper intake manifold). No idea on the cost of the sensor. Call the isuzu parts counter at www.stcharlesauto.com Merlin is usually the guy there.

Joel

additional Notes. I tried different octanes, gas stations. No change. I'm averaging 14 -15 MPG. I stalled twice today back to back. No real indication. No rough idle no delay on acceleration. nothing. I pulled over and did a complete shut down and restarted the car. It disappeared. I never had this ping problem until the cel light came indicating the egr valve problem. The light never came back on. I wonder if perhaps one or two cylinders are not getting the nox that you speak about. But that it works just enough to keep the computer satisfied. I cleaned the egr intake with carb cleaner only as it was running and used a pipe cleaner.