I have an 88 B2 XLT with a 2.9. I changed the auto trany with a FM145 4spd with OD. My problem is, I did a basic tune up (plugs, wires cap and rotor and ignition coil) to solve a light stutter with the engine. The tune up did not solve the problem, so I scanned the EEC and got the code for low voltage from the TPS. I changed it out with a new one and that problem went away. Now the truck hitches whenever I try to accelerate moderatly, or up any hill grade. When in neutral engine will rev through all RPM ranges just fine. Also, I have no problems in 1st gear. I think it may be a vacume line problem, so can anyone help me find a line diagram? Here is a list of all parts that I have worked on, or replaced. thermostat, spark plugs, ignition wires, cap and rotor, ignition coil. throttle position senser, locking fuel cap, air filter, Here is a list of part that are missing or not connected prior to changeing TPS and are still not connected, EGR vacume lines, top vacume line on the back drivers side of upper intake is not connected. Also would Missing Anti lock brake parts cause this problem?....PLEASE HELP ME!!!

 

Did you replace the EEC computer when you swapped transmissons?

re:hitches

I do not know exactly what you mean except maybe it bogs down and jerks?

You need the EGR hooked up on the EFI vehicles and on your year vehicle it should have an EGR sensor too. The sensor can go bad and not throw a code. Usually just gets carboned up. The reason it kind of flat spots is at Wide Open Throttle the EGR valve is suppose to be shut off (reason it has a vacuum tube) when there is no vacuum so it does not dump exhaust gas into the intake stream.

Without the vacuum connected it is never dumping exhaust gas, but, the compuuter thinks it is. So it is adjusting the fuel mix to compensate for the error going by the 02 sensor information.

So, you are going to have driveability problems until the vacuum system is running properly along with the EGR system.

What you should do is get a vacuum gauge to make sure you have at least 17 at idle and that it drops to 0 at WOT. Especially on EFI vehicles you have to make sure the PCV system is working properly too.

> Also would Missing Anti lock brake parts cause this problem

No.

 

Thanks for the info, I am still lookong for a vacume line diagram so I can find out where the lines go, lines are missing from the EGR. The engine seems to missfire, non consistantly and causis the the truck to jerk. But only when there is a load on the engine. Also can I put an 86 EEC for a standard in an 88 that had an automatic?