97 JGC Problem - Highway/High Speed Driving

Bobbo78 · #1 01-15-2005, 08:26 AM

When I'm driving my 97 Jeep GC on the highway at speeds above 60, it will start to shake and lose speed/rpms and I will have my foot on the gas. Sometimes it will jolt and resume other times, the engine will completely stop. The dealer couldn't find anything wrong with it...he said he did some highway driving with it and it didnt happen when he drove it. Some people told me it was the throttle position sensor, others told me it was the steering stabilizer. Please help.

Thanks.

Bobbo78 · #2 01-15-2005, 11:08 PM

Bump

JUSTJEEPS · #3 01-16-2005, 08:41 AM

How about fuel pressure?

dksob81 · #4 01-16-2005, 10:20 AM

Tps.

Sunbeam2 · #5 01-16-2005, 10:38 AM

I had the exact same problem in my 97 Limited V-8. After a few hours on the turnpike it would buck and kick and I could not drive any faster then 55 mph
I changed the Distributer Cap and rotor that is a big PITA to do, and both were seriously worn.
Most Important I changed the TPS also. I just came back last night from a 600 mile round trip to Tampa and the problem has gone away completly. I was on edge the whole time just waiting for it to start. I think the problem was the TPS. Papco Auto Parts got me the sensor for 32 bucks. Jeep wanted 89 for it. Papco said they have seen that problem a lot, When the sensor warms up, normally after several hours it malfunctions. I hope this helps you. This list helped me to find my problem

Bobbo78 · #6 01-16-2005, 08:22 PM

Would the TPS be the Throttle Position Sensor?

dksob81 · #7 01-17-2005, 02:39 AM

Yes it would be. TPS - Throttle Position Sensor

Sunbeam2 · #8 01-17-2005, 06:00 PM

Do not buy the TPS from Jeep they want 89.00 bucks for it. Either papco or discount auto has it for less then 35.00

Bobbo78 · #9 01-22-2005, 03:59 AM

Well, I took it to a local trusted mechanic and he said he checked it thoroughly. (I made a list of all the suggestions you guys gave me.) He said the fuel pump is bad. Could that be the problem? Thanks again for all your help.

McCann · #10 01-24-2005, 10:24 AM

Bobbo,

That sounds very similar to a problem I had 2 years ago with our 97GC. Almost exact.

Everyone thought I was nuts when I said it was the fuel pump. (It had also happened once before when going to a different dealer with a different Jeep, so I was pretty sure). The Jeep dealer finally agreed that it could be but the extended warranty said they wouldn't pay for it.

I finally got the dealer to agree to replace the fuel pump at their cost and the extended warranty to reimburse them if it fixed the problem. If it did not fix the problem...then I would pay for it. It did the trick!

The dealer tried, but never could replicate the problem.

Here is why IMO:

When the tech(s) take our vehicles for a drive they may drive them for a few minutes and maybe up to 10-15 minutes to see if they can get it to do what we say. They may try to get it to do it by letting the truck idle to get it warmed up and then drive it. They check computer codes.

When we owners have many of our problems, the vehicle has been running at over 2000 RPM for an extended time (at highway speed). The dealer can not do this due to time and cost factors. So they don't get the extended high speed use or heat build up in certain components like we do when driving 1-7 hours on the highway. We have a problem, take it in, and listen to many of them tell us we are nuts...there is no problem.

They rely on their computers to give them the answers. The computers are only as good as the person and info used to program them. I think some things are not programmed into the system at time of manufacture of our trucks because Jeep simply did not know the problem could exist.

I absolutely know for a fact...both with my tranny (see other thread) and the fuel pump...not all scenerios were/are programmed into their computer diagnostics. If they are, the computer diagnostics could not solve the riddle.

Ask your mechanic to give you a rebate on labor if it does not solve the problem...if he is confident he is right, he shouldn't balk at that.

Good luck...Mike

Sunbeam2 · #11 01-26-2005, 10:28 AM

I thought my fuel filter was bad when I had my similar problem, but since the filter and pump are one unit on the 97 GC limited and very expensive, jeep tested it and pronounced it OK. After changing the TPS the problem has gone away. If it ever occurs again I will change that filter/pump assembly.

dksob81 · #12 01-26-2005, 12:14 PM

Just to try to clear this up:

The TPS is located on the throttle body at the end of the thottle shaft. By monitoring the output voltage from the TPS, the PCM can determine fuel delivery based on throttle valve angle (Driver Demand). A broken or loosen throttle position sensor can cause intermittant bursts of fuel from the injectors and an unstable idle b/c of the PCM thinks the throttle is moving.

Bobbo78 · #13 02-03-2005, 03:15 PM

Well, I officially broke down completely on Tuesday Morning. I was driving to the DMV which is about 20 mins away and the jeep just stopped. I pulled to the side of the road and it would start but it would just rumble and the RPM would spike to 4000 at times when I tapped the gas. Anyway, I towed it back to the mechanic who changed my fuel pump sensor. He said he was going to have someone from Jeep come and help him out. I got the word today that they had to change the onboard computer. Could that have been the cause of all my problems?

Thanks.

POST REPLY TO THIS THREAD