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Discussion Starter #1
Hi I just was given a 1990 Fleetwood 4.5L Fwd sedan I picked it up in Washington state where I had to cut the catilatic converter off before the trip (to Texas) cause it was clogged I put in a straight pipe but did route the air hose from the emission system back into the straight pipe that had previously gone to the cat. The car ran fine untill i got to some 100 degree weather were it started to surge at freeway speed and lose power. I then put octane booster in the car and it ran fine for another two full tanks then it did it again and the octane booster did not help anymore but it did help to drive the car below 90 degree weather (drove at night when cooler) but now I made it to Texas and the car now surges and loses power alot more but again only in the heat of the day at its worse I could not go above 35mph and at 35 it surged ALOT. I've since replaced the TPS unit, I replaced the fuel filter twice the second seemed clean but replaced anyway, dropped the fuel tank to find no loose baffles or debris, replaced the thermistat and flushed the radiator, I've also listened to all 8 injectors with a long screwdriver and they all seem to be clicking fine at idle, I've also taken the throttle body off and cleaned it, the power steering resivour does seem to push fluide out the cap sometimes while running but when i check it cold it is between the recomended cold lines on the dip stick, the only codes it displays is E40 and E49 I clear the pcm but they come back quickly. any help would be greatly appreciated Im running out of ideas! Thanks
 

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I have similar problems although it happens much less frequently than you describe. Interestingly, I also get the AIR management error code (E49).

I have yet to do as suggested on this board, test for fuel pressure; this is a bit of a PIA to do since the gauge must be routed outside the engine bay onto the windshield so you can read and see whether pressure drops when the surge happens. If so, there is a good chance the fuel pump is on the way out.

When you experience this problem again, you can try to turn the engine off for a few minutes, mine usually runs fine after even a short pause.

Let's see for other responses. You may want to post in the HT4100 section of this board for more exposure.
 

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Discussion Starter #3
Thanks caddynewby I re-posted it over on that board. I tried the shutting off and waiting a while trick also but it comes back within minutes on a hot day. I think I am gonna try checking the fuel pressure when its doing it thanks again.
 
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