99 Tahoe electrical/engine/trans problem

[99Tah]

Hello forum members. New member here. I hope the knowledgeable can help. I have a 99 Tahoe, 4 wd, 5.7. Replacement engine by "Jasper". Since I can't find the paperwork readily, I will estimate mileage at 65-70k. Trannys been replaced as well. The truck has approx 202k on the odometer. Fuel pump/regulator replaced approx 2 years ago. The truck recently developed an electrical gremlin. First the fuel gauge needle would vibrate as to make the needle blurry. I lived with that without adverse effect. Approx. 4 weeks ago, the speedo has been jumping all over the place. It moves from 30-60 or 20-70 etc. When the speedo jumps, the car drives as if the tranny, or the electrical or fuel system mommentarily cuts out. Then comes back on again. I don't really see the tach reving as if the tranny is slipping. No codes are showing. Last code approx 2 weeks ago for an o2 sensor which I changed. I took the car to a trans shop today, and as expected, the truck drove without incident. No speedo malfunction. The problem is intermittent. I am thinking possibly a computer issue with the trans, but since no code are popping I am at a loss. Only other issue is the light is on for the ABS. I do not know if that is connected somehow. Any help would be greatly appreciated. Thanks. Gregg

[Phantm6]

Hey Gregg,
I've been having the same issues resently also. I have had my 99 Tahoe to four different dealers and replaced Trans., Fuel pump, sensors and chased down problems w/the theft deterent system and oh ya there is a miss firing issue also. Now I'm have the same issues you are having and my Mechanic tells me that the Dash cluster is going bad, the circuit board on the back of the dash board. ($300.00 to replace). That's the direction we are heading now, and they say that the circuit board could be causing most of the problems. I don,t know weather I should keep the truck or dump it, I paid $7,000.00 a year ago and repair cost so far adds up to $5,500.00. So good luck and I will let you know what happens to mine.

phantm6

[j cAT]

both you guys remove the battery ground ,,,then remove and clean every ground you can find...then see if it is good.....

these are usually ground problems when all kinds of weird stuff happens..

especially when engines and transmissions are replaced those mechanics are tough on the connectors,and wiring...

also they don't have any respect for, the wire harness coverings, and body secure points..

good luck....

[TxStetson]

99tah,
You might want to pull the dash cluster out and check the plug at the back and see if there is any dirt, dust, or corrosion on the contacts of the plug itself. If you look at the pc board on the back of the cluster you can trace the ckt path and see which contacts control your speedo and gas gage.

[99Tah]

Thanks for the suggestions. I will try them. Any idea on how easy it is to remove the dash cluster? Directions?

Anyone have an opinion as to the vehicle speed sensors being the issue? Thanks

Phantom, sorry to hear of your troubles. I hope they resolve themselves without much more money spent on your part. I will let you know what happens on this end.