Bill Wilson
Newbie
Posts: 1
Loc: Longview, TX
Reg: 10-08-24
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 10-08-24 04:54 PM - Post#2874523
Been driving this since 1994. I think it has around 300K of use. The odometer went kaput at 93K in 1997. Has been dead reliable until something comes out (PU coil, fuel pump, EGR valve).Drove it once or twice each month from March 2018 to March 2023 when it stayed parked until July 2024. Ran OK with the CEL coming on while driving (EGR) that stayed off when restarted. Also lost power driving up long grades. Decided to look into that later. Had to put the van back to use in July so filled the tank with 2 bottles of B12 added. I noticed that the CEL wasn't lighting up when driven at speeds over 45 mph. Was getting 6 mpg so ran another full tank with 2 bottles of B12. That improved the mpgs to 9. Refilled the tank with 2 bottles of Berryman's Fuel Injector Cleaner added.That improved it to 12.5 mpgs. Both products smoothed out the idle tho at times it would have a rough idle that would disappear. Otherwise it now ran great with no loss of power when traveling up steep road grades. Then one day I parked the van then restarted the engine 1 hour later to find it wouldn't idle without stalling out and wouldn't rev up. So I checked for vacuum leaks to find four caused by mice gnawing on the barb connectors (EGR valve, EGR solenoid,A.I.R. solenoid). They also dislodged the EVAP connector at the TBI. Don't know when that occurred, other than between April 2018 and July 2023. I repaired those which didn't help. The ICM was replaced in 1996 when the pickup coil was replaced so I installed a new one . That made a slight improvement so I replaced the IAC since it was installed at the factory. Now it would start and idle if I kept pumping the pedal and would rev up but would stumble and backfire.The IAC instructions said to drive at 40 mph for a period of time so the ECM could set the idle yet I couldn't do that due to the engine stalling when set into gear (TH400). My van is stuck at a Walmart parking lot so a old guy stopped by to help. Told him everything soo he looks at the idle speed screw and throttle cam. Said there end of the screw has worn down and the cam has a divot where it met the screw. He raised the idle slowly by setting strips cut from a cigarette box as shims between the screw and cam until the engine was idling smoothly without using the gas pedal. The engine also kept running when the trans was set in R and D. I thanked him and allowed the engine to idle for 30 minutes to charge up the battery.Shut it down for the night and this morning it back to idling briefly before starting to stall, won't rev up without missing and backfiring. Tried a relearning method of disconnecting the battery to clear the memory then jumping A&B before leaving the ignition on RUN for one minute. That didn't help it idle any better so tried starting the engine after removing my aluminum beer can shim. That made no difference so am stuck trying to figure this out. I did remove the MAP sensor vacuum line to test the ECM. It threw the CEL code for low vacuum which didn't reappear after resetting the vacuum line. I could use some advice on how to get this running back to normal again. I have an in-dash vacuum gauge that showed a steady 20 lbs. when it first started idling normally with the shims installed.
Edited by Bill Wilson on 10-08-24 04:57 PM. Reason for edit: No reason given.
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