If your crossfire is stumbling around 4000 rpm’s or lower, it most
likely has a problem that must be corrected before the X-Ram is added.
There are 3 major points to check:

1) If the fuel filter has not been change in the last 12 months or 10K
miles, change it.

2) If the engine is still stumbling, the one major cause it the fuel pump. The book says that the injectors require 9 to 13psi. The crossfire will not run properly on any pressure under 13psi, no exceptions! The engine will run lean and the power band will drop in rpm’s. This will be more noticeable as gear changes become higher. Only 1 out of 10 stock fuel pumps will flow the required 19psi to correctly function on the crossfire injection system. Purchase a new 85 tuned port fuel pump and a new wiring connector to replace it with. The 85 pump will produce 45 psi and the left injector will keep the pressure regulated to 13 psi without any problems.

3) The last thing is the Distributor. A quick check is to remove the cap and pull up on the rotor.
If the rotor moves up and backwards at the same time, there is shaft play. The distributor can be replaced, but there is a less expensive way to fix it. You can purchase a shaft shim kit at most any performance auto supply (buy 2) for around $8. Just remove the drive gear using a 1/8" pin punch and add enough shims to remove the end-play. You want about the thickness of a piece of notebook paper for clearance or .003” to .005”.

If the engine is stalling during hot day or dying when coming up to a stoplight.

The design of the Crossfire is the major cause of this problem. Gas puddles in the bottom of the Crossfire during normal driving. When coming to a stop, this gas splashes over the restrictions (cast edges in the bottom) and causing a flooding, stumbling or dying situation.

Engine backfires when taking from a light or engine is sluggish during accelerating.

1) If no modifications have been made to the engine (rocker replacement or valve adjustment) the problem will be in the electronic spark control or the coil.

The Timing Control Module is located inside the Distributor, when this unit becomes weak, it will cause the engine to backfire when the engine starts to pull harder then normal (idle speed).

It has been found that both Module and Coil should be replaced at the same time. Because the module is balanced to the impedance of the coil, old coils have a lower impedance.

Also there are two models of coils used on the Crossfire, signified by either a white or yellow wire going to the coil. Many times, the coils are so old that it is hard to distinguish between the two colors (white looks yellow).

You can use either color as long as they are changed as a set.

2) If you have adjusted the valves or installed new lifters or rockers, and the problem has accrued after that, then it is time to readjust the valves again. The valve lash is to tight.

Refer to the end of the installation guide for Valve Adjustments.

Stock rockers are set to 3/4 turn after free play has been removed and 1.6:1 rockers require only ½ turn, 3/4 turn is to tight and will cause the valves not to close all the way.

3) If a valve adjustment was performed to resolve a backfiring problem and did not work, replace the coil and module, and possibly readjust the valves again.