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hello all, i am new to the board, and i am actually posting for my fathers truck, i own a probe, and we have a similar forum over at performanceprobe.com.
anyhow, its a 92 XLT with the 302. e40d trans. just replaced the timing chain cover, water pump, upper intake plenum, and plugs and wires. havent checked the timing, and the fuel filter is 198,000 miles old.
whenever you step into the gas about half way, the engine hesitates real bad, almost as if to stall. but then when you floor it, its almost as if it clears its throat and has power, but not full power. when cruising down the road at normal speeds, at certain intervals of time, the engine will act like someone just let their foot off the gas or something, the engine will almost die, then you punch it and itll come back to life. i think that the timing isnt advanced far enough (retarded too much), and that the fuel filter is probably clogged. any other suggestions? any opinions would be appreciated! thanks
Have you got the codes from it? If not take it to autozone, they will pull the codes and write them down, bring them back here and post them and someone will help you figure something out. Or a haynes manual would show you how to do a self test.
When did this all start? Before or after all the above was replaced? later
I owned a (lord help me) GMC for a while with a 350, and it would do similar things if I did not change the fuel filter every 25k miles. 198k on a fuel filter? Thats crazy high, they should be changed every 25k, and they are cheap, even if that's not the problem I would start there before doing anything else.
-Justin-
YOu may be right, I know little to nothing about efi, but I have been told that there could be a trouble code and the check engine light not come on. Then again I am not certain on all aspects of efi right at this moment.
when did this all start happening before or after your installation of a bunch of parts?
ok, replaced the fuel filter. didnt really do much, surprisingly, it does run a little better, but also i did notice the check engine light is coming on intermittently, when cruising, before it acts like someone took their foot off the gas. if you accelerate, or let off the gas, it goes away. gettin late tonight, ill run the codes tomorrow, i have all the paperwork for eec-iv. thanks for the help guys, please continue to let me know if you think of anything...
I would do a fuel system check. If it's worth it to you, but a fuel pressure gauge for $20-30 so that you can see what your fuel pressure is. If the fuel pressure is low, it will hesitate like you mention when you punch it, and then run crappily at higher RPM's. Your pressure should be around 35-40 psi when running.
The check engine light is your EGR valve telling you that is is stuck open or not at the proper postion at a certain speed. Remove the EGR vacuum line, plug it then drive the truck.
Did this cure the problem? If it did, you need to check the EVR soleniod and see if it is working. Also Check the EVP sensor on the EGR valve for proper operation. the Haynes manual tells you how to test this sensor.