98 Tahoe misses at 2200 RPM and 72 mph

[LastOne]

I wish you the best of luck, all thoses parts are not cheap, I know. If you plan on keeping the truck, go ahead, good maint. If you may sell due to the sticking valves, leave it alone and trade it now. My $$$$ long term is on the sticking valve guide problem...

[magarcia00]

Yesterday the tahoe would barely run after running decently in the morning. This morning I (barely) made it to the dealer and they confirmed that the miss and the stalling/back-fire of the engine was a bad fuel pump. The Crankshaft sensor went out, they will de-carbonize the injector system and I should be good to go!!

[j cAT]

Originally Posted by magarcia00

Yesterday the tahoe would barely run after running decently in the morning. This morning I (barely) made it to the dealer and they confirmed that the miss and the stalling/back-fire of the engine was a bad fuel pump. The Crankshaft sensor went out, they will de-carbonize the injector system and I should be good to go!!

you have stated at 89k mi fuel pump replaced. what name of pump is it as this failure is premature. i hope they guarrantee that what they replace will fix this problem in writing........good luck!

[magarcia00]

I installed new Die-hard battery (last silver model lasted 7+ years!!!), new AC Delco plugs, wires, cap, rotor and fuel filter ($335) and now the dealer hit me for $1450 for the injector system maintenance, replace crankshaft sensor, drop the tank and replace the fuel pump! Last fuel pump lasted 47K miles and the original lasted 89K. Oh well. the truck is solid and worth a lot more to me then the actual value and it has been extremely well maintenained with a ton of extras like 20 inch rims, brush guard, KC hi-lites fog lamps, borla exhaust, Hypertech chip, Cold-Air K&N intake, etc.,. i can't afford to part with this awesome truck. Chevy trucks are the BEST!!!

[mmoss10]

How did they diagnose the crank shaft sensor?

[magarcia00]

Yes, I agree that the fuel pump prematurely failed at 47K miles, but it was replaced by a non-dealer garage and I am sure those electrical pumps have a warranty that is much less then what life I got out of it. Also, the dealer wont guarantee anything verbally nor in writing but my Tahoe felt from the first time it started missing that the fuel was not getting to where it needed to be. It got progressivley worse and the dealer confirmed that this was a fuel pump. All along I felt like it was some sort of fuel line issue, but I still dont think my issue was valve guides. Last night when i barely got to my garage, I re-turned the computer programming to the original factory settings, i personally received the P0339 crankshaft sensor code on my analyzer. The technician also saw it after I cleared the problem and I was told it was an electrical item that goes out often and there was no further comments from the guy! This truck died on me 9 times yesterday under full load and 3 times this morning going to the dealer. The engine idles perfectly, but when put under load, the pump cant get the fuel to the intake. This is a fuel issue and not a valve guide issue! I am a mechanical engineer and I have known to be wrong at times, but this is a classic case of a fuel system issue. Valve guides?? Still trying to figure that one out. I am scratching my head.

[mmoss10]

$1450 sounds like $1100 labor! That's a little steep! Might be worth getting your soft, clean, engineer hands dirty! Thanks for keeping us updated. I can't wait to see if this fixes your truck. I replaced my pump assembly with a new AC pump that I bought from the dealer. I still had the miss, so the next morning I used the Seafoam. Maybe it took that long for my computer to adjust to the new pump? Maybe the pump did solve my problem. Oh no, that means my precious Seafoam is not Magic!!!!!!!

[magarcia00]

Thanks for your comments.... I really don't have a garage set up to drop the tank and change the pump although i could do it. Time is of concern as well, as I leave this week for the Dominican Republic and there are some jobs that I just wont do!! Changing the fuel pump and a system injection flush is something for the dealers....Yea, there is 80% or better of the charge that is labor, but that is life now-a-days. I did everything that I could do for the unit. After using the Sea Foam, my problem worsened. Sure it was coincidence, but I saw no benefit from it. I am sure the work the dealer will do will be acceptable and the problem should go away. Are you still thinking valve guides?? Actually, if you take into account my labor rate, the dealer is cheap....

[mmoss10]

Nice one on the labor rate. You win. I'm glad you got the joke. That proves to me that you really are an engineer! I think you're on the right track. I really don't know if the "valve guide" issue is valid. I do find it interesting that about the crank sensor. I might look deeper into that for my having to run the higher octaine gas. I've never seen that code on my scanner, but it's not a fancy one. I still think that labor rate is outrageous, but if it fixes the problem, it will probably be cheaper than the route I took to fix mine. Let us know if it fixes it. Good luck and have a safe trip!

[magarcia00]

Thanks MMoss....I knew where you were coming from. You must have sense of humor when dealing with automotive issues!! Thanks for staying on top of my issue and your advice. I will pick the Tahoe up next Friday night when i get back into the US! I just researched the crankshaft sensor and I understand that this has nothing to do with the missing fuel to the engine intake issue. Possibly the tremendous amount of shaking, kicking and backfiring caused this electic sensor to go on me or it was a coincidence. It did show up last night for the first time. Also, the AC-Delco fuel pumps have a warranty of 12K miles and/or 12 months and I had my original changed out in April of 2003 for $678 in Missouri by a small garage and at that time I had the wires and plugs changed and injectors flushed! This guy towed my Tahoe in as the pump just quit on me one evening. Been 4 and a half years and prices do go up. At that time the pump was $225. Huge on the labor rate as GM engineers really crucified this design on having the pump in the tank. They have their reasons, but the good ole days were easier on us hands-on guys. I have not seen the dealer breakdown, but when i get the bill they know they have seriously inflated prices and I might be able to get a couple hundred bucks knocked off. These guys are criminals in the charge for service department at the dealers. Amazing he wanted $89 for a fuel filter install. I bought my luberfiner at Autozone for $7.99. Unbelievable!!!!! took me 15 minutes to change out!!

[richiehat]

98 tahoe same thing but i just put new bridgestone tires on and thats when this chatter started so far after one week in the shop we found the tires have gone out of bal three times twice where i bought them and at repair shop good after bal two- three days tires out again did all cap rotor plugs wires pcv fuel filter air filter check and replaced u joint rear shaft checked ft.slip yoke trans check for lockup all good ,tires must be difected

[cjttmyers]

My '99 Yukon had the exact same issue and I replaced the distributor and it fixted the issue. I was told the bushing in the distributor wear out and let the shaft move at higher speeds. Been fine for a year now since it was replaced.